diff --git a/CHANGELOG.md b/CHANGELOG.md
index 7bea9d6d..f7e118ac 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -9,6 +9,20 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Added
 
+- New method `Redmine\Api\Attachment::fromHttpClient()` for creating the class.
+- New method `Redmine\Api\CustomField::fromHttpClient()` for creating the class.
+- New method `Redmine\Api\Group::fromHttpClient()` for creating the class.
+- New method `Redmine\Api\Issue::fromHttpClient()` for creating the class.
+- New method `Redmine\Api\IssueCategory::fromHttpClient()` for creating the class.
+- New method `Redmine\Api\IssuePriority::fromHttpClient()` for creating the class.
+- New method `Redmine\Api\IssueRelation::fromHttpClient()` for creating the class.
+- New method `Redmine\Api\IssueStatus::fromHttpClient()` for creating the class.
+- New method `Redmine\Api\Membership::fromHttpClient()` for creating the class.
+- New method `Redmine\Api\News::fromHttpClient()` for creating the class.
+- New method `Redmine\Api\Project::fromHttpClient()` for creating the class.
+- New method `Redmine\Api\Query::fromHttpClient()` for creating the class.
+- New method `Redmine\Api\Role::fromHttpClient()` for creating the class.
+- New method `Redmine\Api\Search::fromHttpClient()` for creating the class.
 - Add support for PHP 8.5
 - Add support for Redmine 6.1.
 
@@ -16,6 +30,37 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 - Behaviour-driven tests are run against Redmine 6.1.0, 6.0.7, 5.1.10.
 
+### Deprecated
+
+- `Redmine\Api\Attachment::__construct()` is deprecated and will be set to private in future, use `\Redmine\Api\Attachment::fromHttpClient()` instead.
+- Extending `Redmine\Api\Attachment` is deprecated and will be set to final in future, create a wrapper class instead.
+- `Redmine\Api\CustomField::__construct()` is deprecated and will be set to private in future, use `\Redmine\Api\CustomField::fromHttpClient()` instead.
+- Extending `Redmine\Api\CustomField` is deprecated and will be set to final in future, create a wrapper class instead.
+- `Redmine\Api\Group::__construct()` is deprecated and will be set to private in future, use `\Redmine\Api\Group::fromHttpClient()` instead.
+- Extending `Redmine\Api\Group` is deprecated and will be set to final in future, create a wrapper class instead.
+- `Redmine\Api\Issue::__construct()` is deprecated and will be set to private in future, use `\Redmine\Api\Issue::fromHttpClient()` instead.
+- Extending `Redmine\Api\Issue` is deprecated and will be set to final in future, create a wrapper class instead.
+- `Redmine\Api\IssueCategory::__construct()` is deprecated and will be set to private in future, use `\Redmine\Api\IssueCategory::fromHttpClient()` instead.
+- Extending `Redmine\Api\IssueCategory` is deprecated and will be set to final in future, create a wrapper class instead.
+- `Redmine\Api\IssuePriority::__construct()` is deprecated and will be set to private in future, use `\Redmine\Api\IssuePriority::fromHttpClient()` instead.
+- Extending `Redmine\Api\IssuePriority` is deprecated and will be set to final in future, create a wrapper class instead.
+- `Redmine\Api\IssueRelation::__construct()` is deprecated and will be set to private in future, use `\Redmine\Api\IssueRelation::fromHttpClient()` instead.
+- Extending `Redmine\Api\IssueRelation` is deprecated and will be set to final in future, create a wrapper class instead.
+- `Redmine\Api\IssueStatus::__construct()` is deprecated and will be set to private in future, use `\Redmine\Api\IssueStatus::fromHttpClient()` instead.
+- Extending `Redmine\Api\IssueStatus` is deprecated and will be set to final in future, create a wrapper class instead.
+- `Redmine\Api\Membership::__construct()` is deprecated and will be set to private in future, use `\Redmine\Api\Membership::fromHttpClient()` instead.
+- Extending `Redmine\Api\Membership` is deprecated and will be set to final in future, create a wrapper class instead.
+- `Redmine\Api\News::__construct()` is deprecated and will be set to private in future, use `\Redmine\Api\News::fromHttpClient()` instead.
+- Extending `Redmine\Api\News` is deprecated and will be set to final in future, create a wrapper class instead.
+- `Redmine\Api\Project::__construct()` is deprecated and will be set to private in future, use `\Redmine\Api\Project::fromHttpClient()` instead.
+- Extending `Redmine\Api\Project` is deprecated and will be set to final in future, create a wrapper class instead.
+- `Redmine\Api\Query::__construct()` is deprecated and will be set to private in future, use `\Redmine\Api\Query::fromHttpClient()` instead.
+- Extending `Redmine\Api\Query` is deprecated and will be set to final in future, create a wrapper class instead.
+- `Redmine\Api\Role::__construct()` is deprecated and will be set to private in future, use `\Redmine\Api\Role::fromHttpClient()` instead.
+- Extending `Redmine\Api\Role` is deprecated and will be set to final in future, create a wrapper class instead.
+- `Redmine\Api\Search::__construct()` is deprecated and will be set to private in future, use `\Redmine\Api\Search::fromHttpClient()` instead.
+- Extending `Redmine\Api\Search` is deprecated and will be set to final in future, create a wrapper class instead.
+
 ### Removed
 
 - Drop support for Redmine 5.0.x.
diff --git a/composer.json b/composer.json
index 4fd3296e..2171762c 100644
--- a/composer.json
+++ b/composer.json
@@ -64,6 +64,10 @@
         "coverage": "phpunit -c tests/phpunit-coverage.xml.dist --coverage-html=\".phpunit.cache/code-coverage\"",
         "phpstan": "phpstan analyze --memory-limit 512M --configuration .phpstan.neon",
         "phpunit": "phpunit -c phpunit.xml.dist",
+        "rectify": [
+            "@rector",
+            "@codestyle"
+        ],
         "rector": "rector -c .rector.php",
         "test": [
             "@phpstan",
diff --git a/src/Redmine/Api/Attachment.php b/src/Redmine/Api/Attachment.php
index fb9fd8c4..59cba24b 100644
--- a/src/Redmine/Api/Attachment.php
+++ b/src/Redmine/Api/Attachment.php
@@ -2,8 +2,10 @@
 
 namespace Redmine\Api;
 
+use Redmine\Client\Client;
 use Redmine\Exception\SerializerException;
 use Redmine\Exception\UnexpectedResponseException;
+use Redmine\Http\HttpClient;
 use Redmine\Http\HttpFactory;
 use Redmine\Serializer\JsonSerializer;
 use Redmine\Serializer\PathSerializer;
@@ -17,6 +19,37 @@
  */
 class Attachment extends AbstractApi
 {
+    final public static function fromHttpClient(HttpClient $httpClient): self
+    {
+        return new self($httpClient, true);
+    }
+
+    /**
+     * @deprecated v2.9.0 Use fromHttpClient() instead.
+     * @see Attachment::fromHttpClient()
+     *
+     * @param Client|HttpClient $client
+     */
+    public function __construct($client/*, bool $privatelyCalled = false*/)
+    {
+        $privatelyCalled = (func_num_args() > 1) ? func_get_arg(1) : false;
+
+        if ($privatelyCalled === true) {
+            parent::__construct($client);
+
+            return;
+        }
+
+        if (static::class !== self::class) {
+            $className = (new \ReflectionClass($this))->isAnonymous() ? '' : ' in `' . static::class . '`';
+            @trigger_error('Class `' . self::class . '` will declared as final in v3.0.0, stop extending it' . $className . '.', E_USER_DEPRECATED);
+        } else {
+            @trigger_error('Method `' . __METHOD__ . '()` is deprecated since v2.9.0 and will declared as private in v3.0.0, use `' . self::class . '::fromHttpClient()` instead.', E_USER_DEPRECATED);
+        }
+
+        parent::__construct($client);
+    }
+
     /**
      * Get extended information about an attachment.
      *
diff --git a/src/Redmine/Api/CustomField.php b/src/Redmine/Api/CustomField.php
index 4460e43f..53d3497d 100644
--- a/src/Redmine/Api/CustomField.php
+++ b/src/Redmine/Api/CustomField.php
@@ -2,9 +2,11 @@
 
 namespace Redmine\Api;
 
+use Redmine\Client\Client;
 use Redmine\Exception;
 use Redmine\Exception\SerializerException;
 use Redmine\Exception\UnexpectedResponseException;
+use Redmine\Http\HttpClient;
 
 /**
  * Listing custom fields.
@@ -15,6 +17,11 @@
  */
 class CustomField extends AbstractApi
 {
+    final public static function fromHttpClient(HttpClient $httpClient): self
+    {
+        return new self($httpClient, true);
+    }
+
     /**
      * @var null|array<mixed>
      */
@@ -25,6 +32,32 @@ class CustomField extends AbstractApi
      */
     private ?array $customFieldNames = null;
 
+    /**
+     * @deprecated v2.9.0 Use fromHttpClient() instead.
+     * @see CustomField::fromHttpClient()
+     *
+     * @param Client|HttpClient $client
+     */
+    public function __construct($client/*, bool $privatelyCalled = false*/)
+    {
+        $privatelyCalled = (func_num_args() > 1) ? func_get_arg(1) : false;
+
+        if ($privatelyCalled === true) {
+            parent::__construct($client);
+
+            return;
+        }
+
+        if (static::class !== self::class) {
+            $className = (new \ReflectionClass($this))->isAnonymous() ? '' : ' in `' . static::class . '`';
+            @trigger_error('Class `' . self::class . '` will declared as final in v3.0.0, stop extending it' . $className . '.', E_USER_DEPRECATED);
+        } else {
+            @trigger_error('Method `' . __METHOD__ . '()` is deprecated since v2.9.0 and will declared as private in v3.0.0, use `' . self::class . '::fromHttpClient()` instead.', E_USER_DEPRECATED);
+        }
+
+        parent::__construct($client);
+    }
+
     /**
      * List custom fields.
      *
diff --git a/src/Redmine/Api/Group.php b/src/Redmine/Api/Group.php
index 08ee0164..cf20a41a 100644
--- a/src/Redmine/Api/Group.php
+++ b/src/Redmine/Api/Group.php
@@ -2,10 +2,12 @@
 
 namespace Redmine\Api;
 
+use Redmine\Client\Client;
 use Redmine\Exception;
 use Redmine\Exception\MissingParameterException;
 use Redmine\Exception\SerializerException;
 use Redmine\Exception\UnexpectedResponseException;
+use Redmine\Http\HttpClient;
 use Redmine\Http\HttpFactory;
 use Redmine\Serializer\JsonSerializer;
 use Redmine\Serializer\PathSerializer;
@@ -21,6 +23,11 @@
  */
 class Group extends AbstractApi
 {
+    final public static function fromHttpClient(HttpClient $httpClient): self
+    {
+        return new self($httpClient, true);
+    }
+
     /**
      * @var null|array<mixed>
      */
@@ -31,6 +38,32 @@ class Group extends AbstractApi
      */
     private ?array $groupNames = null;
 
+    /**
+     * @deprecated v2.9.0 Use fromHttpClient() instead.
+     * @see Group::fromHttpClient()
+     *
+     * @param Client|HttpClient $client
+     */
+    public function __construct($client/*, bool $privatelyCalled = false*/)
+    {
+        $privatelyCalled = (func_num_args() > 1) ? func_get_arg(1) : false;
+
+        if ($privatelyCalled === true) {
+            parent::__construct($client);
+
+            return;
+        }
+
+        if (static::class !== self::class) {
+            $className = (new \ReflectionClass($this))->isAnonymous() ? '' : ' in `' . static::class . '`';
+            @trigger_error('Class `' . self::class . '` will declared as final in v3.0.0, stop extending it' . $className . '.', E_USER_DEPRECATED);
+        } else {
+            @trigger_error('Method `' . __METHOD__ . '()` is deprecated since v2.9.0 and will declared as private in v3.0.0, use `' . self::class . '::fromHttpClient()` instead.', E_USER_DEPRECATED);
+        }
+
+        parent::__construct($client);
+    }
+
     /**
      * List groups.
      *
diff --git a/src/Redmine/Api/Issue.php b/src/Redmine/Api/Issue.php
index 8e40cb3b..a6a1944c 100644
--- a/src/Redmine/Api/Issue.php
+++ b/src/Redmine/Api/Issue.php
@@ -2,11 +2,13 @@
 
 namespace Redmine\Api;
 
+use Redmine\Client\Client;
 use Redmine\Client\NativeCurlClient;
 use Redmine\Client\Psr18Client;
 use Redmine\Exception;
 use Redmine\Exception\SerializerException;
 use Redmine\Exception\UnexpectedResponseException;
+use Redmine\Http\HttpClient;
 use Redmine\Http\HttpFactory;
 use Redmine\Serializer\JsonSerializer;
 use Redmine\Serializer\PathSerializer;
@@ -47,6 +49,11 @@ class Issue extends AbstractApi
      */
     public const PRIO_IMMEDIATE = 5;
 
+    final public static function fromHttpClient(HttpClient $httpClient): self
+    {
+        return new self($httpClient, true);
+    }
+
     /**
      * @var null|IssueCategory
      */
@@ -72,6 +79,32 @@ class Issue extends AbstractApi
      */
     private $userApi = null;
 
+    /**
+     * @deprecated v2.9.0 Use fromHttpClient() instead.
+     * @see Issue::fromHttpClient()
+     *
+     * @param Client|HttpClient $client
+     */
+    public function __construct($client/*, bool $privatelyCalled = false*/)
+    {
+        $privatelyCalled = (func_num_args() > 1) ? func_get_arg(1) : false;
+
+        if ($privatelyCalled === true) {
+            parent::__construct($client);
+
+            return;
+        }
+
+        if (static::class !== self::class) {
+            $className = (new \ReflectionClass($this))->isAnonymous() ? '' : ' in `' . static::class . '`';
+            @trigger_error('Class `' . self::class . '` will declared as final in v3.0.0, stop extending it' . $className . '.', E_USER_DEPRECATED);
+        } else {
+            @trigger_error('Method `' . __METHOD__ . '()` is deprecated since v2.9.0 and will declared as private in v3.0.0, use `' . self::class . '::fromHttpClient()` instead.', E_USER_DEPRECATED);
+        }
+
+        parent::__construct($client);
+    }
+
     /**
      * List issues.
      *
@@ -489,7 +522,7 @@ private function getIssueCategoryApi()
                 /** @var IssueCategory */
                 $issueCategoryApi = $this->client->getApi('issue_category');
             } else {
-                $issueCategoryApi = new IssueCategory($this->getHttpClient());
+                $issueCategoryApi = IssueCategory::fromHttpClient($this->getHttpClient());
             }
 
             $this->issueCategoryApi = $issueCategoryApi;
@@ -508,7 +541,7 @@ private function getIssueStatusApi()
                 /** @var IssueStatus */
                 $issueStatusApi = $this->client->getApi('issue_status');
             } else {
-                $issueStatusApi = new IssueStatus($this->getHttpClient());
+                $issueStatusApi = IssueStatus::fromHttpClient($this->getHttpClient());
             }
 
             $this->issueStatusApi = $issueStatusApi;
@@ -527,7 +560,7 @@ private function getProjectApi()
                 /** @var Project */
                 $projectApi = $this->client->getApi('project');
             } else {
-                $projectApi = new Project($this->getHttpClient());
+                $projectApi = Project::fromHttpClient($this->getHttpClient());
             }
 
             $this->projectApi = $projectApi;
diff --git a/src/Redmine/Api/IssueCategory.php b/src/Redmine/Api/IssueCategory.php
index 4dc73b66..fc225663 100644
--- a/src/Redmine/Api/IssueCategory.php
+++ b/src/Redmine/Api/IssueCategory.php
@@ -2,11 +2,13 @@
 
 namespace Redmine\Api;
 
+use Redmine\Client\Client;
 use Redmine\Exception;
 use Redmine\Exception\InvalidParameterException;
 use Redmine\Exception\MissingParameterException;
 use Redmine\Exception\SerializerException;
 use Redmine\Exception\UnexpectedResponseException;
+use Redmine\Http\HttpClient;
 use Redmine\Http\HttpFactory;
 use Redmine\Serializer\JsonSerializer;
 use Redmine\Serializer\PathSerializer;
@@ -22,6 +24,11 @@
  */
 class IssueCategory extends AbstractApi
 {
+    final public static function fromHttpClient(HttpClient $httpClient): self
+    {
+        return new self($httpClient, true);
+    }
+
     /**
     * @var null|array<mixed>
     */
@@ -32,6 +39,32 @@ class IssueCategory extends AbstractApi
      */
     private array $issueCategoriesNames = [];
 
+    /**
+     * @deprecated v2.9.0 Use fromHttpClient() instead.
+     * @see IssueCategory::fromHttpClient()
+     *
+     * @param Client|HttpClient $client
+     */
+    public function __construct($client/*, bool $privatelyCalled = false*/)
+    {
+        $privatelyCalled = (func_num_args() > 1) ? func_get_arg(1) : false;
+
+        if ($privatelyCalled === true) {
+            parent::__construct($client);
+
+            return;
+        }
+
+        if (static::class !== self::class) {
+            $className = (new \ReflectionClass($this))->isAnonymous() ? '' : ' in `' . static::class . '`';
+            @trigger_error('Class `' . self::class . '` will declared as final in v3.0.0, stop extending it' . $className . '.', E_USER_DEPRECATED);
+        } else {
+            @trigger_error('Method `' . __METHOD__ . '()` is deprecated since v2.9.0 and will declared as private in v3.0.0, use `' . self::class . '::fromHttpClient()` instead.', E_USER_DEPRECATED);
+        }
+
+        parent::__construct($client);
+    }
+
     /**
      * List issue categories for a given project.
      *
diff --git a/src/Redmine/Api/IssuePriority.php b/src/Redmine/Api/IssuePriority.php
index 7bcf505f..e346dc82 100644
--- a/src/Redmine/Api/IssuePriority.php
+++ b/src/Redmine/Api/IssuePriority.php
@@ -2,9 +2,11 @@
 
 namespace Redmine\Api;
 
+use Redmine\Client\Client;
 use Redmine\Exception;
 use Redmine\Exception\SerializerException;
 use Redmine\Exception\UnexpectedResponseException;
+use Redmine\Http\HttpClient;
 
 /**
  * Listing issue priorities.
@@ -15,6 +17,37 @@
  */
 class IssuePriority extends AbstractApi
 {
+    final public static function fromHttpClient(HttpClient $httpClient): self
+    {
+        return new self($httpClient, true);
+    }
+
+    /**
+     * @deprecated v2.9.0 Use fromHttpClient() instead.
+     * @see IssuePriority::fromHttpClient()
+     *
+     * @param Client|HttpClient $client
+     */
+    public function __construct($client/*, bool $privatelyCalled = false*/)
+    {
+        $privatelyCalled = (func_num_args() > 1) ? func_get_arg(1) : false;
+
+        if ($privatelyCalled === true) {
+            parent::__construct($client);
+
+            return;
+        }
+
+        if (static::class !== self::class) {
+            $className = (new \ReflectionClass($this))->isAnonymous() ? '' : ' in `' . static::class . '`';
+            @trigger_error('Class `' . self::class . '` will declared as final in v3.0.0, stop extending it' . $className . '.', E_USER_DEPRECATED);
+        } else {
+            @trigger_error('Method `' . __METHOD__ . '()` is deprecated since v2.9.0 and will declared as private in v3.0.0, use `' . self::class . '::fromHttpClient()` instead.', E_USER_DEPRECATED);
+        }
+
+        parent::__construct($client);
+    }
+
     /**
      * List issue priorities.
      *
diff --git a/src/Redmine/Api/IssueRelation.php b/src/Redmine/Api/IssueRelation.php
index 4b53cb93..4b77269a 100644
--- a/src/Redmine/Api/IssueRelation.php
+++ b/src/Redmine/Api/IssueRelation.php
@@ -2,10 +2,12 @@
 
 namespace Redmine\Api;
 
+use Redmine\Client\Client;
 use Redmine\Exception;
 use Redmine\Exception\MissingParameterException;
 use Redmine\Exception\SerializerException;
 use Redmine\Exception\UnexpectedResponseException;
+use Redmine\Http\HttpClient;
 use Redmine\Http\HttpFactory;
 use Redmine\Serializer\JsonSerializer;
 
@@ -18,6 +20,37 @@
  */
 class IssueRelation extends AbstractApi
 {
+    final public static function fromHttpClient(HttpClient $httpClient): self
+    {
+        return new self($httpClient, true);
+    }
+
+    /**
+     * @deprecated v2.9.0 Use fromHttpClient() instead.
+     * @see IssueRelation::fromHttpClient()
+     *
+     * @param Client|HttpClient $client
+     */
+    public function __construct($client/*, bool $privatelyCalled = false*/)
+    {
+        $privatelyCalled = (func_num_args() > 1) ? func_get_arg(1) : false;
+
+        if ($privatelyCalled === true) {
+            parent::__construct($client);
+
+            return;
+        }
+
+        if (static::class !== self::class) {
+            $className = (new \ReflectionClass($this))->isAnonymous() ? '' : ' in `' . static::class . '`';
+            @trigger_error('Class `' . self::class . '` will declared as final in v3.0.0, stop extending it' . $className . '.', E_USER_DEPRECATED);
+        } else {
+            @trigger_error('Method `' . __METHOD__ . '()` is deprecated since v2.9.0 and will declared as private in v3.0.0, use `' . self::class . '::fromHttpClient()` instead.', E_USER_DEPRECATED);
+        }
+
+        parent::__construct($client);
+    }
+
     /**
      * List relations of the given $issueId.
      *
diff --git a/src/Redmine/Api/IssueStatus.php b/src/Redmine/Api/IssueStatus.php
index 6322de7b..b92c8524 100644
--- a/src/Redmine/Api/IssueStatus.php
+++ b/src/Redmine/Api/IssueStatus.php
@@ -2,9 +2,11 @@
 
 namespace Redmine\Api;
 
+use Redmine\Client\Client;
 use Redmine\Exception;
 use Redmine\Exception\SerializerException;
 use Redmine\Exception\UnexpectedResponseException;
+use Redmine\Http\HttpClient;
 
 /**
  * Listing issue statuses.
@@ -15,6 +17,11 @@
  */
 class IssueStatus extends AbstractApi
 {
+    final public static function fromHttpClient(HttpClient $httpClient): self
+    {
+        return new self($httpClient, true);
+    }
+
     /**
      * @var null|array<mixed>
      */
@@ -25,6 +32,32 @@ class IssueStatus extends AbstractApi
      */
     private ?array $issueStatusNames = null;
 
+    /**
+     * @deprecated v2.9.0 Use fromHttpClient() instead.
+     * @see IssueStatus::fromHttpClient()
+     *
+     * @param Client|HttpClient $client
+     */
+    public function __construct($client/*, bool $privatelyCalled = false*/)
+    {
+        $privatelyCalled = (func_num_args() > 1) ? func_get_arg(1) : false;
+
+        if ($privatelyCalled === true) {
+            parent::__construct($client);
+
+            return;
+        }
+
+        if (static::class !== self::class) {
+            $className = (new \ReflectionClass($this))->isAnonymous() ? '' : ' in `' . static::class . '`';
+            @trigger_error('Class `' . self::class . '` will declared as final in v3.0.0, stop extending it' . $className . '.', E_USER_DEPRECATED);
+        } else {
+            @trigger_error('Method `' . __METHOD__ . '()` is deprecated since v2.9.0 and will declared as private in v3.0.0, use `' . self::class . '::fromHttpClient()` instead.', E_USER_DEPRECATED);
+        }
+
+        parent::__construct($client);
+    }
+
     /**
      * List issue statuses.
      *
diff --git a/src/Redmine/Api/Membership.php b/src/Redmine/Api/Membership.php
index f71fc16f..6cdda7ae 100644
--- a/src/Redmine/Api/Membership.php
+++ b/src/Redmine/Api/Membership.php
@@ -2,11 +2,13 @@
 
 namespace Redmine\Api;
 
+use Redmine\Client\Client;
 use Redmine\Exception;
 use Redmine\Exception\InvalidParameterException;
 use Redmine\Exception\MissingParameterException;
 use Redmine\Exception\SerializerException;
 use Redmine\Exception\UnexpectedResponseException;
+use Redmine\Http\HttpClient;
 use Redmine\Http\HttpFactory;
 use Redmine\Serializer\XmlSerializer;
 use SimpleXMLElement;
@@ -20,6 +22,37 @@
  */
 class Membership extends AbstractApi
 {
+    final public static function fromHttpClient(HttpClient $httpClient): self
+    {
+        return new self($httpClient, true);
+    }
+
+    /**
+     * @deprecated v2.9.0 Use fromHttpClient() instead.
+     * @see Membership::fromHttpClient()
+     *
+     * @param Client|HttpClient $client
+     */
+    public function __construct($client/*, bool $privatelyCalled = false*/)
+    {
+        $privatelyCalled = (func_num_args() > 1) ? func_get_arg(1) : false;
+
+        if ($privatelyCalled === true) {
+            parent::__construct($client);
+
+            return;
+        }
+
+        if (static::class !== self::class) {
+            $className = (new \ReflectionClass($this))->isAnonymous() ? '' : ' in `' . static::class . '`';
+            @trigger_error('Class `' . self::class . '` will declared as final in v3.0.0, stop extending it' . $className . '.', E_USER_DEPRECATED);
+        } else {
+            @trigger_error('Method `' . __METHOD__ . '()` is deprecated since v2.9.0 and will declared as private in v3.0.0, use `' . self::class . '::fromHttpClient()` instead.', E_USER_DEPRECATED);
+        }
+
+        parent::__construct($client);
+    }
+
     /**
      * List memberships for a given project.
      *
diff --git a/src/Redmine/Api/News.php b/src/Redmine/Api/News.php
index 21e964df..94815782 100644
--- a/src/Redmine/Api/News.php
+++ b/src/Redmine/Api/News.php
@@ -2,10 +2,12 @@
 
 namespace Redmine\Api;
 
+use Redmine\Client\Client;
 use Redmine\Exception;
 use Redmine\Exception\InvalidParameterException;
 use Redmine\Exception\SerializerException;
 use Redmine\Exception\UnexpectedResponseException;
+use Redmine\Http\HttpClient;
 
 /**
  * @see   http://www.redmine.org/projects/redmine/wiki/Rest_News
@@ -14,6 +16,37 @@
  */
 class News extends AbstractApi
 {
+    final public static function fromHttpClient(HttpClient $httpClient): self
+    {
+        return new self($httpClient, true);
+    }
+
+    /**
+     * @deprecated v2.9.0 Use fromHttpClient() instead.
+     * @see News::fromHttpClient()
+     *
+     * @param Client|HttpClient $client
+     */
+    public function __construct($client/*, bool $privatelyCalled = false*/)
+    {
+        $privatelyCalled = (func_num_args() > 1) ? func_get_arg(1) : false;
+
+        if ($privatelyCalled === true) {
+            parent::__construct($client);
+
+            return;
+        }
+
+        if (static::class !== self::class) {
+            $className = (new \ReflectionClass($this))->isAnonymous() ? '' : ' in `' . static::class . '`';
+            @trigger_error('Class `' . self::class . '` will declared as final in v3.0.0, stop extending it' . $className . '.', E_USER_DEPRECATED);
+        } else {
+            @trigger_error('Method `' . __METHOD__ . '()` is deprecated since v2.9.0 and will declared as private in v3.0.0, use `' . self::class . '::fromHttpClient()` instead.', E_USER_DEPRECATED);
+        }
+
+        parent::__construct($client);
+    }
+
     /**
      * List news for a given project.
      *
diff --git a/src/Redmine/Api/Project.php b/src/Redmine/Api/Project.php
index 60511f07..1d0a2f82 100755
--- a/src/Redmine/Api/Project.php
+++ b/src/Redmine/Api/Project.php
@@ -3,10 +3,12 @@
 namespace Redmine\Api;
 
 use InvalidArgumentException;
+use Redmine\Client\Client;
 use Redmine\Exception;
 use Redmine\Exception\MissingParameterException;
 use Redmine\Exception\SerializerException;
 use Redmine\Exception\UnexpectedResponseException;
+use Redmine\Http\HttpClient;
 use Redmine\Http\HttpFactory;
 use Redmine\Serializer\JsonSerializer;
 use Redmine\Serializer\PathSerializer;
@@ -22,6 +24,11 @@
  */
 class Project extends AbstractApi
 {
+    final public static function fromHttpClient(HttpClient $httpClient): self
+    {
+        return new self($httpClient, true);
+    }
+
     /**
      * @var null|array<mixed>
      */
@@ -32,6 +39,32 @@ class Project extends AbstractApi
      */
     private ?array $projectNames = null;
 
+    /**
+     * @deprecated v2.9.0 Use fromHttpClient() instead.
+     * @see Project::fromHttpClient()
+     *
+     * @param Client|HttpClient $client
+     */
+    public function __construct($client/*, bool $privatelyCalled = false*/)
+    {
+        $privatelyCalled = (func_num_args() > 1) ? func_get_arg(1) : false;
+
+        if ($privatelyCalled === true) {
+            parent::__construct($client);
+
+            return;
+        }
+
+        if (static::class !== self::class) {
+            $className = (new \ReflectionClass($this))->isAnonymous() ? '' : ' in `' . static::class . '`';
+            @trigger_error('Class `' . self::class . '` will declared as final in v3.0.0, stop extending it' . $className . '.', E_USER_DEPRECATED);
+        } else {
+            @trigger_error('Method `' . __METHOD__ . '()` is deprecated since v2.9.0 and will declared as private in v3.0.0, use `' . self::class . '::fromHttpClient()` instead.', E_USER_DEPRECATED);
+        }
+
+        parent::__construct($client);
+    }
+
     /**
      * List projects.
      *
diff --git a/src/Redmine/Api/Query.php b/src/Redmine/Api/Query.php
index f21ef308..94b8bc00 100644
--- a/src/Redmine/Api/Query.php
+++ b/src/Redmine/Api/Query.php
@@ -2,9 +2,11 @@
 
 namespace Redmine\Api;
 
+use Redmine\Client\Client;
 use Redmine\Exception;
 use Redmine\Exception\SerializerException;
 use Redmine\Exception\UnexpectedResponseException;
+use Redmine\Http\HttpClient;
 
 /**
  * Custom queries retrieval.
@@ -15,6 +17,37 @@
  */
 class Query extends AbstractApi
 {
+    final public static function fromHttpClient(HttpClient $httpClient): self
+    {
+        return new self($httpClient, true);
+    }
+
+    /**
+     * @deprecated v2.9.0 Use fromHttpClient() instead.
+     * @see Query::fromHttpClient()
+     *
+     * @param Client|HttpClient $client
+     */
+    public function __construct($client/*, bool $privatelyCalled = false*/)
+    {
+        $privatelyCalled = (func_num_args() > 1) ? func_get_arg(1) : false;
+
+        if ($privatelyCalled === true) {
+            parent::__construct($client);
+
+            return;
+        }
+
+        if (static::class !== self::class) {
+            $className = (new \ReflectionClass($this))->isAnonymous() ? '' : ' in `' . static::class . '`';
+            @trigger_error('Class `' . self::class . '` will declared as final in v3.0.0, stop extending it' . $className . '.', E_USER_DEPRECATED);
+        } else {
+            @trigger_error('Method `' . __METHOD__ . '()` is deprecated since v2.9.0 and will declared as private in v3.0.0, use `' . self::class . '::fromHttpClient()` instead.', E_USER_DEPRECATED);
+        }
+
+        parent::__construct($client);
+    }
+
     /**
      * Returns the list of all custom queries visible by the user (public and private queries) for all projects.
      *
diff --git a/src/Redmine/Api/Role.php b/src/Redmine/Api/Role.php
index 3f95336d..fb8c99b7 100644
--- a/src/Redmine/Api/Role.php
+++ b/src/Redmine/Api/Role.php
@@ -2,9 +2,11 @@
 
 namespace Redmine\Api;
 
+use Redmine\Client\Client;
 use Redmine\Exception;
 use Redmine\Exception\SerializerException;
 use Redmine\Exception\UnexpectedResponseException;
+use Redmine\Http\HttpClient;
 use Redmine\Http\HttpFactory;
 use Redmine\Serializer\JsonSerializer;
 
@@ -17,6 +19,11 @@
  */
 class Role extends AbstractApi
 {
+    final public static function fromHttpClient(HttpClient $httpClient): self
+    {
+        return new self($httpClient, true);
+    }
+
     /**
      * @var null|array<mixed>
      */
@@ -27,6 +34,32 @@ class Role extends AbstractApi
      */
     private ?array $roleNames = null;
 
+    /**
+     * @deprecated v2.9.0 Use fromHttpClient() instead.
+     * @see Role::fromHttpClient()
+     *
+     * @param Client|HttpClient $client
+     */
+    public function __construct($client/*, bool $privatelyCalled = false*/)
+    {
+        $privatelyCalled = (func_num_args() > 1) ? func_get_arg(1) : false;
+
+        if ($privatelyCalled === true) {
+            parent::__construct($client);
+
+            return;
+        }
+
+        if (static::class !== self::class) {
+            $className = (new \ReflectionClass($this))->isAnonymous() ? '' : ' in `' . static::class . '`';
+            @trigger_error('Class `' . self::class . '` will declared as final in v3.0.0, stop extending it' . $className . '.', E_USER_DEPRECATED);
+        } else {
+            @trigger_error('Method `' . __METHOD__ . '()` is deprecated since v2.9.0 and will declared as private in v3.0.0, use `' . self::class . '::fromHttpClient()` instead.', E_USER_DEPRECATED);
+        }
+
+        parent::__construct($client);
+    }
+
     /**
      * List roles.
      *
diff --git a/src/Redmine/Api/Search.php b/src/Redmine/Api/Search.php
index 6a6f612b..2dc40b87 100644
--- a/src/Redmine/Api/Search.php
+++ b/src/Redmine/Api/Search.php
@@ -2,15 +2,48 @@
 
 namespace Redmine\Api;
 
+use Redmine\Client\Client;
 use Redmine\Exception;
 use Redmine\Exception\SerializerException;
 use Redmine\Exception\UnexpectedResponseException;
+use Redmine\Http\HttpClient;
 
 /**
  * @see   http://www.redmine.org/projects/redmine/wiki/Rest_Search
  */
 class Search extends AbstractApi
 {
+    final public static function fromHttpClient(HttpClient $httpClient): self
+    {
+        return new self($httpClient, true);
+    }
+
+    /**
+     * @deprecated v2.9.0 Use fromHttpClient() instead.
+     * @see Search::fromHttpClient()
+     *
+     * @param Client|HttpClient $client
+     */
+    public function __construct($client/*, bool $privatelyCalled = false*/)
+    {
+        $privatelyCalled = (func_num_args() > 1) ? func_get_arg(1) : false;
+
+        if ($privatelyCalled === true) {
+            parent::__construct($client);
+
+            return;
+        }
+
+        if (static::class !== self::class) {
+            $className = (new \ReflectionClass($this))->isAnonymous() ? '' : ' in `' . static::class . '`';
+            @trigger_error('Class `' . self::class . '` will declared as final in v3.0.0, stop extending it' . $className . '.', E_USER_DEPRECATED);
+        } else {
+            @trigger_error('Method `' . __METHOD__ . '()` is deprecated since v2.9.0 and will declared as private in v3.0.0, use `' . self::class . '::fromHttpClient()` instead.', E_USER_DEPRECATED);
+        }
+
+        parent::__construct($client);
+    }
+
     /**
      * list search results by Query.
      *
diff --git a/tests/Unit/Api/Attachment/DownloadTest.php b/tests/Unit/Api/Attachment/DownloadTest.php
index 87301202..cdcd6c9d 100644
--- a/tests/Unit/Api/Attachment/DownloadTest.php
+++ b/tests/Unit/Api/Attachment/DownloadTest.php
@@ -31,7 +31,7 @@ public function testDownloadReturnsCorrectResponse($id, string $expectedPath, in
         );
 
         // Create the object under test
-        $api = new Attachment($client);
+        $api = Attachment::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame($expectedReturn, $api->download($id));
diff --git a/tests/Unit/Api/Attachment/FromHttpClientTest.php b/tests/Unit/Api/Attachment/FromHttpClientTest.php
new file mode 100644
index 00000000..9387bcfc
--- /dev/null
+++ b/tests/Unit/Api/Attachment/FromHttpClientTest.php
@@ -0,0 +1,21 @@
+<?php
+
+namespace Redmine\Tests\Unit\Api\Attachment;
+
+use PHPUnit\Framework\Attributes\CoversClass;
+use PHPUnit\Framework\TestCase;
+use Redmine\Api\Attachment;
+use Redmine\Http\HttpClient;
+
+#[CoversClass(Attachment::class)]
+class FromHttpClientTest extends TestCase
+{
+    public function testReturnsCorrectObject(): void
+    {
+        $httpClient = $this->createStub(HttpClient::class);
+
+        $api = Attachment::fromHttpClient($httpClient);
+
+        $this->assertInstanceOf(Attachment::class, $api);
+    }
+}
diff --git a/tests/Unit/Api/Attachment/RemoveTest.php b/tests/Unit/Api/Attachment/RemoveTest.php
index 0f21a33c..4384284e 100644
--- a/tests/Unit/Api/Attachment/RemoveTest.php
+++ b/tests/Unit/Api/Attachment/RemoveTest.php
@@ -27,7 +27,7 @@ public function testRemoveReturnsString(): void
             ],
         );
 
-        $api = new Attachment($client);
+        $api = Attachment::fromHttpClient($client);
 
         $this->assertSame('', $api->remove(5));
     }
diff --git a/tests/Unit/Api/Attachment/ShowTest.php b/tests/Unit/Api/Attachment/ShowTest.php
index 9c51b64b..fed26670 100644
--- a/tests/Unit/Api/Attachment/ShowTest.php
+++ b/tests/Unit/Api/Attachment/ShowTest.php
@@ -31,7 +31,7 @@ public function testShowReturnsCorrectResponse($id, string $expectedPath, string
         );
 
         // Create the object under test
-        $api = new Attachment($client);
+        $api = Attachment::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame($expectedReturn, $api->show($id));
diff --git a/tests/Unit/Api/Attachment/UpdateTest.php b/tests/Unit/Api/Attachment/UpdateTest.php
index 02923902..9c3535af 100644
--- a/tests/Unit/Api/Attachment/UpdateTest.php
+++ b/tests/Unit/Api/Attachment/UpdateTest.php
@@ -32,7 +32,7 @@ public function testUpdateReturnsCorrectResponse(int $id, array $params, string
         );
 
         // Create the object under test
-        $api = new Attachment($client);
+        $api = Attachment::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame($expectedReturn, $api->update($id, $params));
@@ -69,7 +69,7 @@ public function testUpdateThrowsUnexpectedResponseException(): void
             ],
         );
 
-        $api = new Attachment($client);
+        $api = Attachment::fromHttpClient($client);
 
         $this->expectException(UnexpectedResponseException::class);
         $this->expectExceptionMessage('The Redmine server replied with an unexpected response.');
diff --git a/tests/Unit/Api/Attachment/UploadTest.php b/tests/Unit/Api/Attachment/UploadTest.php
index 6f1d7540..5183be45 100644
--- a/tests/Unit/Api/Attachment/UploadTest.php
+++ b/tests/Unit/Api/Attachment/UploadTest.php
@@ -31,7 +31,7 @@ public function testUploadReturnsCorrectResponse(string $attachment, array $para
         );
 
         // Create the object under test
-        $api = new Attachment($client);
+        $api = Attachment::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame($expectedReturn, $api->upload($attachment, $params));
diff --git a/tests/Unit/Api/AttachmentTest.php b/tests/Unit/Api/AttachmentTest.php
index a1ab9018..55969996 100644
--- a/tests/Unit/Api/AttachmentTest.php
+++ b/tests/Unit/Api/AttachmentTest.php
@@ -7,6 +7,8 @@
 use PHPUnit\Framework\TestCase;
 use Redmine\Api\Attachment;
 use Redmine\Client\Client;
+use Redmine\Http\HttpClient;
+use Redmine\Tests\Fixtures\AssertingHttpClient;
 
 /**
  * @author     Malte Gerth <mail@malte-gerth.de>
@@ -14,22 +16,76 @@
 #[CoversClass(Attachment::class)]
 class AttachmentTest extends TestCase
 {
+    public function testExtendingTheClassTriggersDeprecationWarning(): void
+    {
+        // PHPUnit 10 compatible way to test trigger_error().
+        set_error_handler(
+            function ($errno, $errstr): bool {
+                $this->assertSame(
+                    'Class `Redmine\Api\Attachment` will declared as final in v3.0.0, stop extending it.',
+                    $errstr,
+                );
+
+                restore_error_handler();
+                return true;
+            },
+            E_USER_DEPRECATED,
+        );
+
+        new class ($this->createStub(HttpClient::class)) extends Attachment {};
+    }
+
+    public function testConstructorTriggersDeprecationWarning(): void
+    {
+        // PHPUnit 10 compatible way to test trigger_error().
+        set_error_handler(
+            function ($errno, $errstr): bool {
+                $this->assertSame(
+                    'Method `Redmine\Api\Attachment::__construct()` is deprecated since v2.9.0 and will declared as private in v3.0.0, use `Redmine\Api\Attachment::fromHttpClient()` instead.',
+                    $errstr,
+                );
+
+                restore_error_handler();
+                return true;
+            },
+            E_USER_DEPRECATED,
+        );
+
+        new Attachment($this->createStub(HttpClient::class));
+    }
+
+    public function testLastCallFailedWithoutPreviousRequestReturnsTrue(): void
+    {
+        $api = Attachment::fromHttpClient($this->createStub(HttpClient::class));
+
+        // Perform the tests
+        $this->assertTrue($api->lastCallFailed());
+    }
+
     /**
      * Test lastCallFailed().
      *
      * @dataProvider responseCodeProvider
      */
     #[DataProvider('responseCodeProvider')]
-    public function testLastCallFailedTrue(int $responseCode, bool $hasFailed): void
+    public function testLastCallFailedReturnsCorrectValue(int $responseCode, bool $hasFailed): void
     {
-        // Create the used mock objects
-        $client = $this->createMock(Client::class);
-        $client->expects($this->once())
-            ->method('getLastResponseStatusCode')
-            ->willReturn($responseCode);
+        $client = AssertingHttpClient::create(
+            $this,
+            [
+                'GET',
+                '/attachments/1.json',
+                'application/json',
+                '',
+                $responseCode,
+                '',
+                '',
+            ],
+        );
 
         // Create the object under test
-        $api = new Attachment($client);
+        $api = Attachment::fromHttpClient($client);
+        $api->show(1);
 
         // Perform the tests
         $this->assertSame($hasFailed, $api->lastCallFailed());
diff --git a/tests/Unit/Api/CustomField/FromHttpClientTest.php b/tests/Unit/Api/CustomField/FromHttpClientTest.php
new file mode 100644
index 00000000..af2e7e41
--- /dev/null
+++ b/tests/Unit/Api/CustomField/FromHttpClientTest.php
@@ -0,0 +1,21 @@
+<?php
+
+namespace Redmine\Tests\Unit\Api\CustomField;
+
+use PHPUnit\Framework\Attributes\CoversClass;
+use PHPUnit\Framework\TestCase;
+use Redmine\Api\CustomField;
+use Redmine\Http\HttpClient;
+
+#[CoversClass(CustomField::class)]
+class FromHttpClientTest extends TestCase
+{
+    public function testReturnsCorrectObject(): void
+    {
+        $httpClient = $this->createStub(HttpClient::class);
+
+        $api = CustomField::fromHttpClient($httpClient);
+
+        $this->assertInstanceOf(CustomField::class, $api);
+    }
+}
diff --git a/tests/Unit/Api/CustomField/ListNamesTest.php b/tests/Unit/Api/CustomField/ListNamesTest.php
index 36153176..d0fcb59f 100644
--- a/tests/Unit/Api/CustomField/ListNamesTest.php
+++ b/tests/Unit/Api/CustomField/ListNamesTest.php
@@ -33,7 +33,7 @@ public function testListNamesReturnsCorrectResponse(string $expectedPath, int $r
         );
 
         // Create the object under test
-        $api = new CustomField($client);
+        $api = CustomField::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame($expectedResponse, $api->listNames());
@@ -98,7 +98,7 @@ public function testListNamesCallsHttpClientOnlyOnce(): void
         );
 
         // Create the object under test
-        $api = new CustomField($client);
+        $api = CustomField::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame([1 => 'CustomField 1'], $api->listNames());
diff --git a/tests/Unit/Api/CustomField/ListTest.php b/tests/Unit/Api/CustomField/ListTest.php
index 4498144e..c1a4fdb3 100644
--- a/tests/Unit/Api/CustomField/ListTest.php
+++ b/tests/Unit/Api/CustomField/ListTest.php
@@ -5,8 +5,8 @@
 use PHPUnit\Framework\Attributes\CoversClass;
 use PHPUnit\Framework\TestCase;
 use Redmine\Api\CustomField;
-use Redmine\Client\Client;
 use Redmine\Exception\UnexpectedResponseException;
+use Redmine\Tests\Fixtures\AssertingHttpClient;
 
 #[CoversClass(CustomField::class)]
 class ListTest extends TestCase
@@ -17,21 +17,21 @@ public function testListWithoutParametersReturnsResponse(): void
         $response = '["API Response"]';
         $expectedResponse = ['API Response'];
 
-        // Create the used mock objects
-        $client = $this->createMock(Client::class);
-        $client->expects($this->once())
-            ->method('requestGet')
-            ->with('/custom_fields.json')
-            ->willReturn(true);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseBody')
-            ->willReturn($response);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseContentType')
-            ->willReturn('application/json');
+        $client = AssertingHttpClient::create(
+            $this,
+            [
+                'GET',
+                '/custom_fields.json',
+                'application/json',
+                '',
+                200,
+                'application/json',
+                $response,
+            ],
+        );
 
         // Create the object under test
-        $api = new CustomField($client);
+        $api = CustomField::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame($expectedResponse, $api->list());
@@ -44,21 +44,21 @@ public function testListWithParametersReturnsResponse(): void
         $response = '["API Response"]';
         $expectedResponse = ['API Response'];
 
-        // Create the used mock objects
-        $client = $this->createMock(Client::class);
-        $client->expects($this->once())
-            ->method('requestGet')
-            ->with('/custom_fields.json?limit=25&offset=0&0=not-used')
-            ->willReturn(true);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseBody')
-            ->willReturn($response);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseContentType')
-            ->willReturn('application/json');
+        $client = AssertingHttpClient::create(
+            $this,
+            [
+                'GET',
+                '/custom_fields.json?limit=25&offset=0&0=not-used',
+                'application/json',
+                '',
+                200,
+                'application/json',
+                $response,
+            ],
+        );
 
         // Create the object under test
-        $api = new CustomField($client);
+        $api = CustomField::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame($expectedResponse, $api->list($allParameters));
@@ -74,23 +74,39 @@ public function testListWithHighLimitParametersReturnsResponse(): void
             'items' => [],
         ];
 
-        // Create the used mock objects
-        $client = $this->createMock(Client::class);
-        $client->expects($this->exactly(3))
-            ->method('requestGet')
-            ->with(
-                $this->stringStartsWith('/custom_fields.json'),
-            )
-            ->willReturn(true);
-        $client->expects($this->exactly(3))
-            ->method('getLastResponseBody')
-            ->willReturn($response);
-        $client->expects($this->exactly(3))
-            ->method('getLastResponseContentType')
-            ->willReturn('application/json');
+        $client = AssertingHttpClient::create(
+            $this,
+            [
+                'GET',
+                '/custom_fields.json?limit=100&offset=0',
+                'application/json',
+                '',
+                200,
+                'application/json',
+                $response,
+            ],
+            [
+                'GET',
+                '/custom_fields.json?limit=100&offset=100',
+                'application/json',
+                '',
+                200,
+                'application/json',
+                $response,
+            ],
+            [
+                'GET',
+                '/custom_fields.json?limit=50&offset=200',
+                'application/json',
+                '',
+                200,
+                'application/json',
+                $response,
+            ],
+        );
 
         // Create the object under test
-        $api = new CustomField($client);
+        $api = CustomField::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame($expectedResponse, $api->list($allParameters));
@@ -108,23 +124,21 @@ public function testListCallsEndpointUntilOffsetIsHigherThanTotalCount(): void
             'items' => [],
         ];
 
-        // Create the used mock objects
-        $client = $this->createMock(Client::class);
-        $client->expects($this->once())
-            ->method('requestGet')
-            ->with(
-                $this->stringStartsWith('/custom_fields.json'),
-            )
-            ->willReturn(true);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseBody')
-            ->willReturn($response);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseContentType')
-            ->willReturn('application/json');
+        $client = AssertingHttpClient::create(
+            $this,
+            [
+                'GET',
+                '/custom_fields.json?limit=100&offset=0',
+                'application/json',
+                '',
+                200,
+                'application/json',
+                $response,
+            ],
+        );
 
         // Create the object under test
-        $api = new CustomField($client);
+        $api = CustomField::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame($returnDataSet, $api->list($allParameters));
@@ -132,21 +146,21 @@ public function testListCallsEndpointUntilOffsetIsHigherThanTotalCount(): void
 
     public function testListThrowsException(): void
     {
-        // Create the used mock objects
-        $client = $this->createMock(Client::class);
-        $client->expects($this->exactly(1))
-            ->method('requestGet')
-            ->with('/custom_fields.json')
-            ->willReturn(true);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseBody')
-            ->willReturn('');
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseContentType')
-            ->willReturn('application/json');
+        $client = AssertingHttpClient::create(
+            $this,
+            [
+                'GET',
+                '/custom_fields.json',
+                'application/json',
+                '',
+                200,
+                'application/json',
+                '',
+            ],
+        );
 
         // Create the object under test
-        $api = new CustomField($client);
+        $api = CustomField::fromHttpClient($client);
 
         $this->expectException(UnexpectedResponseException::class);
         $this->expectExceptionMessage('The Redmine server replied with an unexpected response.');
diff --git a/tests/Unit/Api/CustomFieldTest.php b/tests/Unit/Api/CustomFieldTest.php
index 39811bda..9b4cae8a 100644
--- a/tests/Unit/Api/CustomFieldTest.php
+++ b/tests/Unit/Api/CustomFieldTest.php
@@ -6,8 +6,8 @@
 use PHPUnit\Framework\Attributes\DataProvider;
 use PHPUnit\Framework\TestCase;
 use Redmine\Api\CustomField;
-use Redmine\Client\Client;
-use Redmine\Tests\Fixtures\MockClient;
+use Redmine\Http\HttpClient;
+use Redmine\Tests\Fixtures\AssertingHttpClient;
 
 /**
  * @author     Malte Gerth <mail@malte-gerth.de>
@@ -15,12 +15,50 @@
 #[CoversClass(CustomField::class)]
 class CustomFieldTest extends TestCase
 {
+    public function testExtendingTheClassTriggersDeprecationWarning(): void
+    {
+        // PHPUnit 10 compatible way to test trigger_error().
+        set_error_handler(
+            function ($errno, $errstr): bool {
+                $this->assertSame(
+                    'Class `Redmine\Api\CustomField` will declared as final in v3.0.0, stop extending it.',
+                    $errstr,
+                );
+
+                restore_error_handler();
+                return true;
+            },
+            E_USER_DEPRECATED,
+        );
+
+        new class ($this->createStub(HttpClient::class)) extends CustomField {};
+    }
+
+    public function testConstructorTriggersDeprecationWarning(): void
+    {
+        // PHPUnit 10 compatible way to test trigger_error().
+        set_error_handler(
+            function ($errno, $errstr): bool {
+                $this->assertSame(
+                    'Method `Redmine\Api\CustomField::__construct()` is deprecated since v2.9.0 and will declared as private in v3.0.0, use `Redmine\Api\CustomField::fromHttpClient()` instead.',
+                    $errstr,
+                );
+
+                restore_error_handler();
+                return true;
+            },
+            E_USER_DEPRECATED,
+        );
+
+        new CustomField($this->createStub(HttpClient::class));
+    }
+
     /**
      * Test all().
      */
     public function testAllTriggersDeprecationWarning(): void
     {
-        $api = new CustomField(MockClient::create());
+        $api = CustomField::fromHttpClient($this->createStub(HttpClient::class));
 
         // PHPUnit 10 compatible way to test trigger_error().
         set_error_handler(
@@ -47,21 +85,21 @@ function ($errno, $errstr): bool {
     #[DataProvider('getAllData')]
     public function testAllReturnsClientGetResponse(string $response, string $responseType, $expectedResponse): void
     {
-        // Create the used mock objects
-        $client = $this->createMock(Client::class);
-        $client->expects($this->exactly(1))
-            ->method('requestGet')
-            ->with('/custom_fields.json')
-            ->willReturn(true);
-        $client->expects($this->atLeast(1))
-            ->method('getLastResponseBody')
-            ->willReturn($response);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseContentType')
-            ->willReturn($responseType);
+        $client = AssertingHttpClient::create(
+            $this,
+            [
+                'GET',
+                '/custom_fields.json',
+                'application/json',
+                '',
+                200,
+                $responseType,
+                $response,
+            ],
+        );
 
         // Create the object under test
-        $api = new CustomField($client);
+        $api = CustomField::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame($expectedResponse, $api->all());
@@ -86,23 +124,21 @@ public function testAllReturnsClientGetResponseWithParameters(): void
         $response = '["API Response"]';
         $expectedResponse = ['API Response'];
 
-        // Create the used mock objects
-        $client = $this->createMock(Client::class);
-        $client->expects($this->once())
-            ->method('requestGet')
-            ->with(
-                $this->stringContains('not-used'),
-            )
-            ->willReturn(true);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseBody')
-            ->willReturn($response);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseContentType')
-            ->willReturn('application/json');
+        $client = AssertingHttpClient::create(
+            $this,
+            [
+                'GET',
+                '/custom_fields.json?limit=25&offset=0&0=not-used',
+                'application/json',
+                '',
+                200,
+                'application/json',
+                $response,
+            ],
+        );
 
         // Create the object under test
-        $api = new CustomField($client);
+        $api = CustomField::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame($expectedResponse, $api->all($allParameters));
@@ -121,23 +157,39 @@ public function testAllReturnsClientGetResponseWithHighLimit(): void
             'items' => [],
         ];
 
-        // Create the used mock objects
-        $client = $this->createMock(Client::class);
-        $client->expects($this->exactly(3))
-            ->method('requestGet')
-            ->with(
-                $this->stringStartsWith('/custom_fields.json'),
-            )
-            ->willReturn(true);
-        $client->expects($this->exactly(3))
-            ->method('getLastResponseBody')
-            ->willReturn($response);
-        $client->expects($this->exactly(3))
-            ->method('getLastResponseContentType')
-            ->willReturn('application/json');
+        $client = AssertingHttpClient::create(
+            $this,
+            [
+                'GET',
+                '/custom_fields.json?limit=100&offset=0',
+                'application/json',
+                '',
+                200,
+                'application/json',
+                $response,
+            ],
+            [
+                'GET',
+                '/custom_fields.json?limit=100&offset=100',
+                'application/json',
+                '',
+                200,
+                'application/json',
+                $response,
+            ],
+            [
+                'GET',
+                '/custom_fields.json?limit=50&offset=200',
+                'application/json',
+                '',
+                200,
+                'application/json',
+                $response,
+            ],
+        );
 
         // Create the object under test
-        $api = new CustomField($client);
+        $api = CustomField::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame($expectedResponse, $api->all($allParameters));
@@ -152,23 +204,21 @@ public function testAllCallsEndpointUntilOffsetIsHigherThanTotalCount(): void
         $response = '{"limit":"100","offset":"10","total_count":"5","items":[]}';
         $allParameters = ['limit' => 250];
 
-        // Create the used mock objects
-        $client = $this->createMock(Client::class);
-        $client->expects($this->once())
-            ->method('requestGet')
-            ->with(
-                $this->stringStartsWith('/custom_fields.json'),
-            )
-            ->willReturn(true);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseBody')
-            ->willReturn($response);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseContentType')
-            ->willReturn('application/json');
+        $client = AssertingHttpClient::create(
+            $this,
+            [
+                'GET',
+                '/custom_fields.json?limit=100&offset=0',
+                'application/json',
+                '',
+                200,
+                'application/json',
+                $response,
+            ],
+        );
 
         // Create the object under test
-        $api = new CustomField($client);
+        $api = CustomField::fromHttpClient($client);
 
         // Perform the tests
         $retrievedDataSet = $api->all($allParameters);
@@ -189,23 +239,21 @@ public function testListingReturnsNameIdArray(): void
             'CustomField 5' => 5,
         ];
 
-        // Create the used mock objects
-        $client = $this->createMock(Client::class);
-        $client->expects($this->once())
-            ->method('requestGet')
-            ->with(
-                $this->stringStartsWith('/custom_fields.json'),
-            )
-            ->willReturn(true);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseBody')
-            ->willReturn($response);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseContentType')
-            ->willReturn('application/json');
+        $client = AssertingHttpClient::create(
+            $this,
+            [
+                'GET',
+                '/custom_fields.json',
+                'application/json',
+                '',
+                200,
+                'application/json',
+                $response,
+            ],
+        );
 
         // Create the object under test
-        $api = new CustomField($client);
+        $api = CustomField::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame($expectedReturn, $api->listing());
@@ -223,23 +271,21 @@ public function testListingCallsGetOnlyTheFirstTime(): void
             'CustomField 5' => 5,
         ];
 
-        // Create the used mock objects
-        $client = $this->createMock(Client::class);
-        $client->expects($this->once())
-            ->method('requestGet')
-            ->with(
-                $this->stringStartsWith('/custom_fields.json'),
-            )
-            ->willReturn(true);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseBody')
-            ->willReturn($response);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseContentType')
-            ->willReturn('application/json');
+        $client = AssertingHttpClient::create(
+            $this,
+            [
+                'GET',
+                '/custom_fields.json',
+                'application/json',
+                '',
+                200,
+                'application/json',
+                $response,
+            ],
+        );
 
         // Create the object under test
-        $api = new CustomField($client);
+        $api = CustomField::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame($expectedReturn, $api->listing());
@@ -258,23 +304,30 @@ public function testListingCallsGetEveryTimeWithForceUpdate(): void
             'CustomField 5' => 5,
         ];
 
-        // Create the used mock objects
-        $client = $this->createMock(Client::class);
-        $client->expects($this->exactly(2))
-            ->method('requestGet')
-            ->with(
-                $this->stringStartsWith('/custom_fields.json'),
-            )
-            ->willReturn(true);
-        $client->expects($this->exactly(2))
-            ->method('getLastResponseBody')
-            ->willReturn($response);
-        $client->expects($this->exactly(2))
-            ->method('getLastResponseContentType')
-            ->willReturn('application/json');
+        $client = AssertingHttpClient::create(
+            $this,
+            [
+                'GET',
+                '/custom_fields.json',
+                'application/json',
+                '',
+                200,
+                'application/json',
+                $response,
+            ],
+            [
+                'GET',
+                '/custom_fields.json',
+                'application/json',
+                '',
+                200,
+                'application/json',
+                $response,
+            ],
+        );
 
         // Create the object under test
-        $api = new CustomField($client);
+        $api = CustomField::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame($expectedReturn, $api->listing(true));
@@ -286,15 +339,22 @@ public function testListingCallsGetEveryTimeWithForceUpdate(): void
      */
     public function testListingTriggersDeprecationWarning(): void
     {
-        $client = $this->createStub(Client::class);
-        $client->method('requestGet')
-            ->willReturn(true);
-        $client->method('getLastResponseBody')
-            ->willReturn('{"custom_fields":[{"id":1,"name":"CustomField 1"},{"id":5,"name":"CustomField 5"}]}');
-        $client->method('getLastResponseContentType')
-            ->willReturn('application/json');
+        $response = '{"custom_fields":[{"id":1,"name":"CustomField 1"},{"id":5,"name":"CustomField 5"}]}';
+
+        $client = AssertingHttpClient::create(
+            $this,
+            [
+                'GET',
+                '/custom_fields.json',
+                'application/json',
+                '',
+                200,
+                'application/json',
+                $response,
+            ],
+        );
 
-        $api = new CustomField($client);
+        $api = CustomField::fromHttpClient($client);
 
         // PHPUnit 10 compatible way to test trigger_error().
         set_error_handler(
@@ -321,23 +381,21 @@ public function testGetIdByNameMakesGetRequest(): void
         // Test values
         $response = '{"custom_fields":[{"id":5,"name":"CustomField 5"}]}';
 
-        // Create the used mock objects
-        $client = $this->createMock(Client::class);
-        $client->expects($this->once())
-            ->method('requestGet')
-            ->with(
-                $this->stringStartsWith('/custom_fields.json'),
-            )
-            ->willReturn(true);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseBody')
-            ->willReturn($response);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseContentType')
-            ->willReturn('application/json');
+        $client = AssertingHttpClient::create(
+            $this,
+            [
+                'GET',
+                '/custom_fields.json',
+                'application/json',
+                '',
+                200,
+                'application/json',
+                $response,
+            ],
+        );
 
         // Create the object under test
-        $api = new CustomField($client);
+        $api = CustomField::fromHttpClient($client);
 
         // Perform the tests
         $this->assertFalse($api->getIdByName('CustomField 1'));
@@ -346,15 +404,22 @@ public function testGetIdByNameMakesGetRequest(): void
 
     public function testGetIdByNameTriggersDeprecationWarning(): void
     {
-        $client = $this->createStub(Client::class);
-        $client->method('requestGet')
-            ->willReturn(true);
-        $client->method('getLastResponseBody')
-            ->willReturn('{"custom_fields":[{"id":1,"name":"CustomField 1"},{"id":5,"name":"CustomField 5"}]}');
-        $client->method('getLastResponseContentType')
-            ->willReturn('application/json');
-
-        $api = new CustomField($client);
+        $response = '{"custom_fields":[{"id":1,"name":"CustomField 1"},{"id":5,"name":"CustomField 5"}]}';
+
+        $client = AssertingHttpClient::create(
+            $this,
+            [
+                'GET',
+                '/custom_fields.json',
+                'application/json',
+                '',
+                200,
+                'application/json',
+                $response,
+            ],
+        );
+
+        $api = CustomField::fromHttpClient($client);
 
         // PHPUnit 10 compatible way to test trigger_error().
         set_error_handler(
diff --git a/tests/Unit/Api/Group/AddUserTest.php b/tests/Unit/Api/Group/AddUserTest.php
index cfd15448..3917ed64 100644
--- a/tests/Unit/Api/Group/AddUserTest.php
+++ b/tests/Unit/Api/Group/AddUserTest.php
@@ -32,7 +32,7 @@ public function testAddUserReturnsCorrectResponse(int $groupId, int $userId, str
         );
 
         // Create the object under test
-        $api = new Group($client);
+        $api = Group::fromHttpClient($client);
 
         // Perform the tests
         $return = $api->addUser($groupId, $userId);
@@ -74,7 +74,7 @@ public function testAddUserReturnsEmptyString(): void
         );
 
         // Create the object under test
-        $api = new Group($client);
+        $api = Group::fromHttpClient($client);
 
         // Perform the tests
         $return = $api->addUser(1, 2);
diff --git a/tests/Unit/Api/Group/CreateTest.php b/tests/Unit/Api/Group/CreateTest.php
index 13ae0b3c..2c3621c6 100644
--- a/tests/Unit/Api/Group/CreateTest.php
+++ b/tests/Unit/Api/Group/CreateTest.php
@@ -36,7 +36,7 @@ public function testCreateReturnsCorrectResponse(array $parameters, string $expe
         );
 
         // Create the object under test
-        $api = new Group($client);
+        $api = Group::fromHttpClient($client);
 
         // Perform the tests
         $return = $api->create($parameters);
@@ -123,7 +123,7 @@ public function testCreateReturnsEmptyString(): void
         );
 
         // Create the object under test
-        $api = new Group($client);
+        $api = Group::fromHttpClient($client);
 
         // Perform the tests
         $return = $api->create(['name' => 'Group Name']);
@@ -140,7 +140,7 @@ public function testCreateThrowsExceptionIfNameIsMissing(): void
         $client = $this->createStub(HttpClient::class);
 
         // Create the object under test
-        $api = new Group($client);
+        $api = Group::fromHttpClient($client);
 
         $this->expectException(MissingParameterException::class);
         $this->expectExceptionMessage('Theses parameters are mandatory: `name`');
diff --git a/tests/Unit/Api/Group/FromHttpClientTest.php b/tests/Unit/Api/Group/FromHttpClientTest.php
new file mode 100644
index 00000000..ceed94b1
--- /dev/null
+++ b/tests/Unit/Api/Group/FromHttpClientTest.php
@@ -0,0 +1,21 @@
+<?php
+
+namespace Redmine\Tests\Unit\Api\Group;
+
+use PHPUnit\Framework\Attributes\CoversClass;
+use PHPUnit\Framework\TestCase;
+use Redmine\Api\Group;
+use Redmine\Http\HttpClient;
+
+#[CoversClass(Group::class)]
+class FromHttpClientTest extends TestCase
+{
+    public function testReturnsCorrectObject(): void
+    {
+        $httpClient = $this->createStub(HttpClient::class);
+
+        $api = Group::fromHttpClient($httpClient);
+
+        $this->assertInstanceOf(Group::class, $api);
+    }
+}
diff --git a/tests/Unit/Api/Group/ListNamesTest.php b/tests/Unit/Api/Group/ListNamesTest.php
index 14b413b7..91c5a456 100644
--- a/tests/Unit/Api/Group/ListNamesTest.php
+++ b/tests/Unit/Api/Group/ListNamesTest.php
@@ -33,7 +33,7 @@ public function testListNamesReturnsCorrectResponse(string $expectedPath, int $r
         );
 
         // Create the object under test
-        $api = new Group($client);
+        $api = Group::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame($expectedResponse, $api->listNames());
@@ -98,7 +98,7 @@ public function testListNamesCallsHttpClientOnlyOnce(): void
         );
 
         // Create the object under test
-        $api = new Group($client);
+        $api = Group::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame([1 => 'Group 1'], $api->listNames());
diff --git a/tests/Unit/Api/Group/ListTest.php b/tests/Unit/Api/Group/ListTest.php
index 7d5c4d17..b082ef02 100644
--- a/tests/Unit/Api/Group/ListTest.php
+++ b/tests/Unit/Api/Group/ListTest.php
@@ -5,8 +5,8 @@
 use PHPUnit\Framework\Attributes\CoversClass;
 use PHPUnit\Framework\TestCase;
 use Redmine\Api\Group;
-use Redmine\Client\Client;
 use Redmine\Exception\UnexpectedResponseException;
+use Redmine\Tests\Fixtures\AssertingHttpClient;
 
 #[CoversClass(Group::class)]
 class ListTest extends TestCase
@@ -17,21 +17,21 @@ public function testListWithoutParametersReturnsResponse(): void
         $response = '["API Response"]';
         $expectedReturn = ['API Response'];
 
-        // Create the used mock objects
-        $client = $this->createMock(Client::class);
-        $client->expects($this->once())
-            ->method('requestGet')
-            ->with('/groups.json')
-            ->willReturn(true);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseBody')
-            ->willReturn($response);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseContentType')
-            ->willReturn('application/json');
+        $client = AssertingHttpClient::create(
+            $this,
+            [
+                'GET',
+                '/groups.json',
+                'application/json',
+                '',
+                200,
+                'application/json',
+                $response,
+            ],
+        );
 
         // Create the object under test
-        $api = new Group($client);
+        $api = Group::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame($expectedReturn, $api->list());
@@ -44,21 +44,21 @@ public function testListeWithParametersReturnsResponse(): void
         $response = '["API Response"]';
         $expectedReturn = ['API Response'];
 
-        // Create the used mock objects
-        $client = $this->createMock(Client::class);
-        $client->expects($this->once())
-            ->method('requestGet')
-            ->with('/groups.json?limit=25&offset=0&0=not-used')
-            ->willReturn(true);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseBody')
-            ->willReturn($response);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseContentType')
-            ->willReturn('application/json');
+        $client = AssertingHttpClient::create(
+            $this,
+            [
+                'GET',
+                '/groups.json?limit=25&offset=0&0=not-used',
+                'application/json',
+                '',
+                200,
+                'application/json',
+                $response,
+            ],
+        );
 
         // Create the object under test
-        $api = new Group($client);
+        $api = Group::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame($expectedReturn, $api->list($parameters));
@@ -66,21 +66,21 @@ public function testListeWithParametersReturnsResponse(): void
 
     public function testListThrowsException(): void
     {
-        // Create the used mock objects
-        $client = $this->createMock(Client::class);
-        $client->expects($this->exactly(1))
-            ->method('requestGet')
-            ->with('/groups.json')
-            ->willReturn(true);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseBody')
-            ->willReturn('');
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseContentType')
-            ->willReturn('application/json');
+        $client = AssertingHttpClient::create(
+            $this,
+            [
+                'GET',
+                '/groups.json',
+                'application/json',
+                '',
+                200,
+                'application/json',
+                '',
+            ],
+        );
 
         // Create the object under test
-        $api = new Group($client);
+        $api = Group::fromHttpClient($client);
 
         $this->expectException(UnexpectedResponseException::class);
         $this->expectExceptionMessage('The Redmine server replied with an unexpected response.');
diff --git a/tests/Unit/Api/Group/RemoveTest.php b/tests/Unit/Api/Group/RemoveTest.php
index d89205b8..6f9a18e9 100644
--- a/tests/Unit/Api/Group/RemoveTest.php
+++ b/tests/Unit/Api/Group/RemoveTest.php
@@ -27,7 +27,7 @@ public function testRemoveReturnsString(): void
             ],
         );
 
-        $api = new Group($client);
+        $api = Group::fromHttpClient($client);
 
         $this->assertSame('', $api->remove(5));
     }
diff --git a/tests/Unit/Api/Group/RemoveUserTest.php b/tests/Unit/Api/Group/RemoveUserTest.php
index fb9a94b4..cb9c5bea 100644
--- a/tests/Unit/Api/Group/RemoveUserTest.php
+++ b/tests/Unit/Api/Group/RemoveUserTest.php
@@ -27,7 +27,7 @@ public function testRemoveUserReturnsString(): void
             ],
         );
 
-        $api = new Group($client);
+        $api = Group::fromHttpClient($client);
 
         $this->assertSame('', $api->removeUser(5, 10));
     }
diff --git a/tests/Unit/Api/Group/ShowTest.php b/tests/Unit/Api/Group/ShowTest.php
index 0fbc4275..21b3822c 100644
--- a/tests/Unit/Api/Group/ShowTest.php
+++ b/tests/Unit/Api/Group/ShowTest.php
@@ -31,7 +31,7 @@ public function testShowReturnsCorrectResponse($groupId, array $params, string $
         );
 
         // Create the object under test
-        $api = new Group($client);
+        $api = Group::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame($expectedReturn, $api->show($groupId, $params));
diff --git a/tests/Unit/Api/Group/UpdateTest.php b/tests/Unit/Api/Group/UpdateTest.php
index d039e3ba..15014e77 100644
--- a/tests/Unit/Api/Group/UpdateTest.php
+++ b/tests/Unit/Api/Group/UpdateTest.php
@@ -33,7 +33,7 @@ public function testUpdateReturnsCorrectResponse(int $id, array $parameters, str
         );
 
         // Create the object under test
-        $api = new Group($client);
+        $api = Group::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame('', $api->update($id, $parameters));
diff --git a/tests/Unit/Api/GroupTest.php b/tests/Unit/Api/GroupTest.php
index ba05217d..5e87bfd9 100644
--- a/tests/Unit/Api/GroupTest.php
+++ b/tests/Unit/Api/GroupTest.php
@@ -8,8 +8,8 @@
 use PHPUnit\Framework\Attributes\DataProvider;
 use PHPUnit\Framework\TestCase;
 use Redmine\Api\Group;
-use Redmine\Client\Client;
-use Redmine\Tests\Fixtures\MockClient;
+use Redmine\Http\HttpClient;
+use Redmine\Tests\Fixtures\AssertingHttpClient;
 
 /**
  * @author     Malte Gerth <mail@malte-gerth.de>
@@ -17,12 +17,50 @@
 #[CoversClass(Group::class)]
 class GroupTest extends TestCase
 {
+    public function testExtendingTheClassTriggersDeprecationWarning(): void
+    {
+        // PHPUnit 10 compatible way to test trigger_error().
+        set_error_handler(
+            function ($errno, $errstr): bool {
+                $this->assertSame(
+                    'Class `Redmine\Api\Group` will declared as final in v3.0.0, stop extending it.',
+                    $errstr,
+                );
+
+                restore_error_handler();
+                return true;
+            },
+            E_USER_DEPRECATED,
+        );
+
+        new class ($this->createStub(HttpClient::class)) extends Group {};
+    }
+
+    public function testConstructorTriggersDeprecationWarning(): void
+    {
+        // PHPUnit 10 compatible way to test trigger_error().
+        set_error_handler(
+            function ($errno, $errstr): bool {
+                $this->assertSame(
+                    'Method `Redmine\Api\Group::__construct()` is deprecated since v2.9.0 and will declared as private in v3.0.0, use `Redmine\Api\Group::fromHttpClient()` instead.',
+                    $errstr,
+                );
+
+                restore_error_handler();
+                return true;
+            },
+            E_USER_DEPRECATED,
+        );
+
+        new Group($this->createStub(HttpClient::class));
+    }
+
     /**
      * Test all().
      */
     public function testAllTriggersDeprecationWarning(): void
     {
-        $api = new Group(MockClient::create());
+        $api = Group::fromHttpClient($this->createStub(HttpClient::class));
 
         // PHPUnit 10 compatible way to test trigger_error().
         set_error_handler(
@@ -49,21 +87,21 @@ function ($errno, $errstr): bool {
     #[DataProvider('getAllData')]
     public function testAllReturnsClientGetResponse(string $response, string $responseType, $expectedResponse): void
     {
-        // Create the used mock objects
-        $client = $this->createMock(Client::class);
-        $client->expects($this->exactly(1))
-            ->method('requestGet')
-            ->with('/groups.json')
-            ->willReturn(true);
-        $client->expects($this->atLeast(1))
-            ->method('getLastResponseBody')
-            ->willReturn($response);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseContentType')
-            ->willReturn($responseType);
+        $client = AssertingHttpClient::create(
+            $this,
+            [
+                'GET',
+                '/groups.json',
+                'application/json',
+                '',
+                200,
+                $responseType,
+                $response,
+            ],
+        );
 
         // Create the object under test
-        $api = new Group($client);
+        $api = Group::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame($expectedResponse, $api->all());
@@ -88,26 +126,21 @@ public function testAllReturnsClientGetResponseWithParameters(): void
         $response = '["API Response"]';
         $expectedReturn = ['API Response'];
 
-        // Create the used mock objects
-        $client = $this->createMock(Client::class);
-        $client->expects($this->once())
-            ->method('requestGet')
-            ->with(
-                $this->logicalAnd(
-                    $this->stringStartsWith('/groups.json'),
-                    $this->stringContains('not-used'),
-                ),
-            )
-            ->willReturn(true);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseBody')
-            ->willReturn($response);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseContentType')
-            ->willReturn('application/json');
+        $client = AssertingHttpClient::create(
+            $this,
+            [
+                'GET',
+                '/groups.json?limit=25&offset=0&0=not-used',
+                'application/json',
+                '',
+                200,
+                'application/json',
+                $response,
+            ],
+        );
 
         // Create the object under test
-        $api = new Group($client);
+        $api = Group::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame($expectedReturn, $api->all($parameters));
@@ -118,15 +151,22 @@ public function testAllReturnsClientGetResponseWithParameters(): void
      */
     public function testListingTriggersDeprecationWarning(): void
     {
-        $client = $this->createStub(Client::class);
-        $client->method('requestGet')
-            ->willReturn(true);
-        $client->method('getLastResponseBody')
-            ->willReturn('{"groups":[{"id":1,"name":"Group 1"},{"id":5,"name":"Group 5"}]}');
-        $client->method('getLastResponseContentType')
-            ->willReturn('application/json');
+        $response = '{"groups":[{"id":1,"name":"Group 1"},{"id":5,"name":"Group 5"}]}';
 
-        $api = new Group($client);
+        $client = AssertingHttpClient::create(
+            $this,
+            [
+                'GET',
+                '/groups.json',
+                'application/json',
+                '',
+                200,
+                'application/json',
+                $response,
+            ],
+        );
+
+        $api = Group::fromHttpClient($client);
 
         // PHPUnit 10 compatible way to test trigger_error().
         set_error_handler(
@@ -157,23 +197,21 @@ public function testListingReturnsNameIdArray(): void
             'Group 5' => 5,
         ];
 
-        // Create the used mock objects
-        $client = $this->createMock(Client::class);
-        $client->expects($this->once())
-            ->method('requestGet')
-            ->with(
-                $this->stringStartsWith('/groups.json'),
-            )
-            ->willReturn(true);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseBody')
-            ->willReturn($response);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseContentType')
-            ->willReturn('application/json');
+        $client = AssertingHttpClient::create(
+            $this,
+            [
+                'GET',
+                '/groups.json',
+                'application/json',
+                '',
+                200,
+                'application/json',
+                $response,
+            ],
+        );
 
         // Create the object under test
-        $api = new Group($client);
+        $api = Group::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame($expectedReturn, $api->listing());
@@ -191,23 +229,21 @@ public function testListingCallsGetOnlyTheFirstTime(): void
             'Group 5' => 5,
         ];
 
-        // Create the used mock objects
-        $client = $this->createMock(Client::class);
-        $client->expects($this->once())
-            ->method('requestGet')
-            ->with(
-                $this->stringStartsWith('/groups.json'),
-            )
-            ->willReturn(true);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseBody')
-            ->willReturn($response);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseContentType')
-            ->willReturn('application/json');
+        $client = AssertingHttpClient::create(
+            $this,
+            [
+                'GET',
+                '/groups.json',
+                'application/json',
+                '',
+                200,
+                'application/json',
+                $response,
+            ],
+        );
 
         // Create the object under test
-        $api = new Group($client);
+        $api = Group::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame($expectedReturn, $api->listing());
@@ -226,23 +262,30 @@ public function testListingCallsGetEveryTimeWithForceUpdate(): void
             'Group 5' => 5,
         ];
 
-        // Create the used mock objects
-        $client = $this->createMock(Client::class);
-        $client->expects($this->exactly(2))
-            ->method('requestGet')
-            ->with(
-                $this->stringStartsWith('/groups.json'),
-            )
-            ->willReturn(true);
-        $client->expects($this->exactly(2))
-            ->method('getLastResponseBody')
-            ->willReturn($response);
-        $client->expects($this->exactly(2))
-            ->method('getLastResponseContentType')
-            ->willReturn('application/json');
+        $client = AssertingHttpClient::create(
+            $this,
+            [
+                'GET',
+                '/groups.json',
+                'application/json',
+                '',
+                200,
+                'application/json',
+                $response,
+            ],
+            [
+                'GET',
+                '/groups.json',
+                'application/json',
+                '',
+                200,
+                'application/json',
+                $response,
+            ],
+        );
 
         // Create the object under test
-        $api = new Group($client);
+        $api = Group::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame($expectedReturn, $api->listing(true));
diff --git a/tests/Unit/Api/Issue/AddNoteToIssueTest.php b/tests/Unit/Api/Issue/AddNoteToIssueTest.php
index af5a9dc0..99fff46b 100644
--- a/tests/Unit/Api/Issue/AddNoteToIssueTest.php
+++ b/tests/Unit/Api/Issue/AddNoteToIssueTest.php
@@ -33,7 +33,7 @@ public function testAddNoteToIssueReturnsCorrectResponse(int $id, string $note,
         );
 
         // Create the object under test
-        $api = new Issue($client);
+        $api = Issue::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame('', $api->addNoteToIssue($id, $note, $isPrivate));
diff --git a/tests/Unit/Api/Issue/AddWatcherTest.php b/tests/Unit/Api/Issue/AddWatcherTest.php
index 868807e1..c92ddc25 100644
--- a/tests/Unit/Api/Issue/AddWatcherTest.php
+++ b/tests/Unit/Api/Issue/AddWatcherTest.php
@@ -32,7 +32,7 @@ public function testAddWatcherReturnsCorrectResponse(int $issueId, int $watcherU
         );
 
         // Create the object under test
-        $api = new Issue($client);
+        $api = Issue::fromHttpClient($client);
 
         // Perform the tests
         $return = $api->addWatcher($issueId, $watcherUserId);
@@ -74,7 +74,7 @@ public function testAddWatcherReturnsEmptyString(): void
         );
 
         // Create the object under test
-        $api = new Issue($client);
+        $api = Issue::fromHttpClient($client);
 
         // Perform the tests
         $return = $api->addWatcher(1, 2);
diff --git a/tests/Unit/Api/Issue/AttachManyTest.php b/tests/Unit/Api/Issue/AttachManyTest.php
index f88bf247..2e9631ab 100644
--- a/tests/Unit/Api/Issue/AttachManyTest.php
+++ b/tests/Unit/Api/Issue/AttachManyTest.php
@@ -31,7 +31,7 @@ public function testAttachManyReturnsCorrectResponse(int $issueId, array $parame
         );
 
         // AttachMany the object under test
-        $api = new Issue($client);
+        $api = Issue::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame('', $api->attachMany($issueId, $parameters));
diff --git a/tests/Unit/Api/Issue/AttachTest.php b/tests/Unit/Api/Issue/AttachTest.php
index 5ccd2641..0949289c 100644
--- a/tests/Unit/Api/Issue/AttachTest.php
+++ b/tests/Unit/Api/Issue/AttachTest.php
@@ -31,7 +31,7 @@ public function testAttachReturnsCorrectResponse(int $issueId, array $parameters
         );
 
         // Attach the object under test
-        $api = new Issue($client);
+        $api = Issue::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame('', $api->attach($issueId, $parameters));
diff --git a/tests/Unit/Api/Issue/CreateTest.php b/tests/Unit/Api/Issue/CreateTest.php
index 09e1e1b9..edb2648f 100644
--- a/tests/Unit/Api/Issue/CreateTest.php
+++ b/tests/Unit/Api/Issue/CreateTest.php
@@ -32,7 +32,7 @@ public function testCreateReturnsCorrectResponse(array $parameters, string $expe
         );
 
         // Create the object under test
-        $api = new Issue($client);
+        $api = Issue::fromHttpClient($client);
 
         // Perform the tests
         $return = $api->create($parameters);
@@ -248,7 +248,7 @@ public function testCreateReturnsEmptyString(): void
         );
 
         // Create the object under test
-        $api = new Issue($client);
+        $api = Issue::fromHttpClient($client);
 
         // Perform the tests
         $return = $api->create([]);
@@ -281,7 +281,7 @@ public function testCreateWithHttpClientRetrievesIssueStatusId(): void
         );
 
         // Create the object under test
-        $api = new Issue($client);
+        $api = Issue::fromHttpClient($client);
 
         // Perform the tests
         $xmlElement = $api->create(['status' => 'Status Name']);
@@ -318,7 +318,7 @@ public function testCreateWithHttpClientRetrievesProjectId(): void
         );
 
         // Create the object under test
-        $api = new Issue($client);
+        $api = Issue::fromHttpClient($client);
 
         // Perform the tests
         $xmlElement = $api->create(['project' => 'Project Name']);
@@ -355,7 +355,7 @@ public function testCreateWithHttpClientRetrievesIssueCategoryId(): void
         );
 
         // Create the object under test
-        $api = new Issue($client);
+        $api = Issue::fromHttpClient($client);
 
         // Perform the tests
         $xmlElement = $api->create(['project_id' => 3, 'category' => 'Category Name']);
@@ -392,7 +392,7 @@ public function testCreateWithHttpClientRetrievesTrackerId(): void
         );
 
         // Create the object under test
-        $api = new Issue($client);
+        $api = Issue::fromHttpClient($client);
 
         // Perform the tests
         $xmlElement = $api->create(['tracker' => 'Tracker Name']);
@@ -429,7 +429,7 @@ public function testCreateWithHttpClientRetrievesUserId(): void
         );
 
         // Create the object under test
-        $api = new Issue($client);
+        $api = Issue::fromHttpClient($client);
 
         // Perform the tests
         $xmlElement = $api->create(['assigned_to' => 'user_6', 'author' => 'user_5']);
@@ -524,7 +524,7 @@ public function testCreateWithClientCleansParameters(): void
         ];
 
         // Create the object under test
-        $api = new Issue($client);
+        $api = Issue::fromHttpClient($client);
 
         // Perform the tests
         $xmlElement = $api->create($parameters);
diff --git a/tests/Unit/Api/Issue/FromHttpClientTest.php b/tests/Unit/Api/Issue/FromHttpClientTest.php
new file mode 100644
index 00000000..ba0d1eb3
--- /dev/null
+++ b/tests/Unit/Api/Issue/FromHttpClientTest.php
@@ -0,0 +1,21 @@
+<?php
+
+namespace Redmine\Tests\Unit\Api\Issue;
+
+use PHPUnit\Framework\Attributes\CoversClass;
+use PHPUnit\Framework\TestCase;
+use Redmine\Api\Issue;
+use Redmine\Http\HttpClient;
+
+#[CoversClass(Issue::class)]
+class FromHttpClientTest extends TestCase
+{
+    public function testReturnsCorrectObject(): void
+    {
+        $httpClient = $this->createStub(HttpClient::class);
+
+        $api = Issue::fromHttpClient($httpClient);
+
+        $this->assertInstanceOf(Issue::class, $api);
+    }
+}
diff --git a/tests/Unit/Api/Issue/ListTest.php b/tests/Unit/Api/Issue/ListTest.php
index 26637a84..22b62068 100644
--- a/tests/Unit/Api/Issue/ListTest.php
+++ b/tests/Unit/Api/Issue/ListTest.php
@@ -5,8 +5,8 @@
 use PHPUnit\Framework\Attributes\CoversClass;
 use PHPUnit\Framework\TestCase;
 use Redmine\Api\Issue;
-use Redmine\Client\Client;
 use Redmine\Exception\UnexpectedResponseException;
+use Redmine\Tests\Fixtures\AssertingHttpClient;
 
 #[CoversClass(Issue::class)]
 class ListTest extends TestCase
@@ -17,21 +17,21 @@ public function testListWithoutParametersReturnsResponse(): void
         $response = '["API Response"]';
         $expectedReturn = ['API Response'];
 
-        // Create the used mock objects
-        $client = $this->createMock(Client::class);
-        $client->expects($this->once())
-            ->method('requestGet')
-            ->with('/issues.json')
-            ->willReturn(true);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseBody')
-            ->willReturn($response);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseContentType')
-            ->willReturn('application/json');
+        $client = AssertingHttpClient::create(
+            $this,
+            [
+                'GET',
+                '/issues.json',
+                'application/json',
+                '',
+                200,
+                'application/json',
+                $response,
+            ],
+        );
 
         // Create the object under test
-        $api = new Issue($client);
+        $api = Issue::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame($expectedReturn, $api->list());
@@ -44,21 +44,21 @@ public function testListWithParametersReturnsResponse(): void
         $response = '["API Response"]';
         $expectedReturn = ['API Response'];
 
-        // Create the used mock objects
-        $client = $this->createMock(Client::class);
-        $client->expects($this->once())
-            ->method('requestGet')
-            ->with('/issues.json?limit=25&offset=0&0=not-used')
-            ->willReturn(true);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseBody')
-            ->willReturn($response);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseContentType')
-            ->willReturn('application/json');
+        $client = AssertingHttpClient::create(
+            $this,
+            [
+                'GET',
+                '/issues.json?limit=25&offset=0&0=not-used',
+                'application/json',
+                '',
+                200,
+                'application/json',
+                $response,
+            ],
+        );
 
         // Create the object under test
-        $api = new Issue($client);
+        $api = Issue::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame($expectedReturn, $api->list($parameters));
@@ -66,21 +66,21 @@ public function testListWithParametersReturnsResponse(): void
 
     public function testListThrowsException(): void
     {
-        // Create the used mock objects
-        $client = $this->createMock(Client::class);
-        $client->expects($this->exactly(1))
-            ->method('requestGet')
-            ->with('/issues.json')
-            ->willReturn(true);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseBody')
-            ->willReturn('');
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseContentType')
-            ->willReturn('application/json');
+        $client = AssertingHttpClient::create(
+            $this,
+            [
+                'GET',
+                '/issues.json',
+                'application/json',
+                '',
+                200,
+                'application/json',
+                '',
+            ],
+        );
 
         // Create the object under test
-        $api = new Issue($client);
+        $api = Issue::fromHttpClient($client);
 
         $this->expectException(UnexpectedResponseException::class);
         $this->expectExceptionMessage('The Redmine server replied with an unexpected response.');
diff --git a/tests/Unit/Api/Issue/RemoveTest.php b/tests/Unit/Api/Issue/RemoveTest.php
index effe5f99..ba5d7015 100644
--- a/tests/Unit/Api/Issue/RemoveTest.php
+++ b/tests/Unit/Api/Issue/RemoveTest.php
@@ -31,7 +31,7 @@ public function testRemoveReturnsCorrectResponse(int $issueId, string $expectedP
         );
 
         // Create the object under test
-        $api = new Issue($client);
+        $api = Issue::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame($response, $api->remove($issueId));
diff --git a/tests/Unit/Api/Issue/RemoveWatcherTest.php b/tests/Unit/Api/Issue/RemoveWatcherTest.php
index 677ef505..baa2d41a 100644
--- a/tests/Unit/Api/Issue/RemoveWatcherTest.php
+++ b/tests/Unit/Api/Issue/RemoveWatcherTest.php
@@ -31,7 +31,7 @@ public function testRemoveWatcherReturnsCorrectResponse(int $issueId, int $watch
         );
 
         // Create the object under test
-        $api = new Issue($client);
+        $api = Issue::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame($response, $api->removeWatcher($issueId, $watcherUserId));
diff --git a/tests/Unit/Api/Issue/SetIssueStatusTest.php b/tests/Unit/Api/Issue/SetIssueStatusTest.php
index a4439f64..6cb24da5 100644
--- a/tests/Unit/Api/Issue/SetIssueStatusTest.php
+++ b/tests/Unit/Api/Issue/SetIssueStatusTest.php
@@ -35,7 +35,7 @@ public function testSetIssueStatusReturnsCorrectResponse(): void
         );
 
         // Create the object under test
-        $api = new Issue($client);
+        $api = Issue::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame('', $api->setIssueStatus(5, 'Status Name'));
diff --git a/tests/Unit/Api/Issue/ShowTest.php b/tests/Unit/Api/Issue/ShowTest.php
index b28a47a2..a1621921 100644
--- a/tests/Unit/Api/Issue/ShowTest.php
+++ b/tests/Unit/Api/Issue/ShowTest.php
@@ -31,7 +31,7 @@ public function testShowReturnsCorrectResponse($issueId, array $params, string $
         );
 
         // Create the object under test
-        $api = new Issue($client);
+        $api = Issue::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame($expectedReturn, $api->show($issueId, $params));
diff --git a/tests/Unit/Api/Issue/UpdateTest.php b/tests/Unit/Api/Issue/UpdateTest.php
index f61c20d4..a352fd51 100644
--- a/tests/Unit/Api/Issue/UpdateTest.php
+++ b/tests/Unit/Api/Issue/UpdateTest.php
@@ -33,7 +33,7 @@ public function testUpdateReturnsCorrectResponse(int $id, array $parameters, str
         );
 
         // Create the object under test
-        $api = new Issue($client);
+        $api = Issue::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame('', $api->update($id, $parameters));
@@ -194,7 +194,7 @@ public function testUpdateCleansParameters(): void
         ];
 
         // Create the object under test
-        $api = new Issue($client);
+        $api = Issue::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame('', $api->update(70, $parameters));
diff --git a/tests/Unit/Api/IssueCategory/CreateTest.php b/tests/Unit/Api/IssueCategory/CreateTest.php
index ecd48568..4900c31f 100644
--- a/tests/Unit/Api/IssueCategory/CreateTest.php
+++ b/tests/Unit/Api/IssueCategory/CreateTest.php
@@ -34,7 +34,7 @@ public function testCreateReturnsCorrectResponse($identifier, array $parameters,
         );
 
         // Create the object under test
-        $api = new IssueCategory($client);
+        $api = IssueCategory::fromHttpClient($client);
 
         // Perform the tests
         $return = $api->create($identifier, $parameters);
@@ -89,7 +89,7 @@ public function testCreateReturnsEmptyString(): void
         );
 
         // Create the object under test
-        $api = new IssueCategory($client);
+        $api = IssueCategory::fromHttpClient($client);
 
         // Perform the tests
         $return = $api->create(5, ['name' => 'Test Category']);
@@ -103,7 +103,7 @@ public function testCreateThrowsExceptionWithEmptyParameters(): void
         $client = $this->createStub(HttpClient::class);
 
         // Create the object under test
-        $api = new IssueCategory($client);
+        $api = IssueCategory::fromHttpClient($client);
 
         $this->expectException(MissingParameterException::class);
         $this->expectExceptionMessage('Theses parameters are mandatory: `name');
@@ -122,7 +122,7 @@ public function testCreateThrowsExceptionIfMandatoyParametersAreMissing(array $p
         $client = $this->createStub(HttpClient::class);
 
         // Create the object under test
-        $api = new IssueCategory($client);
+        $api = IssueCategory::fromHttpClient($client);
 
         $this->expectException(MissingParameterException::class);
         $this->expectExceptionMessage('Theses parameters are mandatory: `name');
diff --git a/tests/Unit/Api/IssueCategory/FromHttpClientTest.php b/tests/Unit/Api/IssueCategory/FromHttpClientTest.php
new file mode 100644
index 00000000..bb51858a
--- /dev/null
+++ b/tests/Unit/Api/IssueCategory/FromHttpClientTest.php
@@ -0,0 +1,21 @@
+<?php
+
+namespace Redmine\Tests\Unit\Api\IssueCategory;
+
+use PHPUnit\Framework\Attributes\CoversClass;
+use PHPUnit\Framework\TestCase;
+use Redmine\Api\IssueCategory;
+use Redmine\Http\HttpClient;
+
+#[CoversClass(IssueCategory::class)]
+class FromHttpClientTest extends TestCase
+{
+    public function testReturnsCorrectObject(): void
+    {
+        $httpClient = $this->createStub(HttpClient::class);
+
+        $api = IssueCategory::fromHttpClient($httpClient);
+
+        $this->assertInstanceOf(IssueCategory::class, $api);
+    }
+}
diff --git a/tests/Unit/Api/IssueCategory/ListByProjectTest.php b/tests/Unit/Api/IssueCategory/ListByProjectTest.php
index 356ec2ff..53c8b5c2 100644
--- a/tests/Unit/Api/IssueCategory/ListByProjectTest.php
+++ b/tests/Unit/Api/IssueCategory/ListByProjectTest.php
@@ -6,10 +6,10 @@
 use PHPUnit\Framework\Attributes\DataProviderExternal;
 use PHPUnit\Framework\TestCase;
 use Redmine\Api\IssueCategory;
-use Redmine\Client\Client;
 use Redmine\Exception\InvalidParameterException;
 use Redmine\Exception\UnexpectedResponseException;
-use Redmine\Tests\Fixtures\MockClient;
+use Redmine\Http\HttpClient;
+use Redmine\Tests\Fixtures\AssertingHttpClient;
 use Redmine\Tests\Fixtures\TestDataProvider;
 
 #[CoversClass(IssueCategory::class)]
@@ -22,21 +22,21 @@ public function testListByProjectWithoutParametersReturnsResponse(): void
         $response = '["API Response"]';
         $expectedReturn = ['API Response'];
 
-        // Create the used mock objects
-        $client = $this->createMock(Client::class);
-        $client->expects($this->once())
-            ->method('requestGet')
-            ->with('/projects/5/issue_categories.json')
-            ->willReturn(true);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseBody')
-            ->willReturn($response);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseContentType')
-            ->willReturn('application/json');
+        $client = AssertingHttpClient::create(
+            $this,
+            [
+                'GET',
+                '/projects/5/issue_categories.json',
+                'application/json',
+                '',
+                200,
+                'application/json',
+                $response,
+            ],
+        );
 
         // Create the object under test
-        $api = new IssueCategory($client);
+        $api = IssueCategory::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame($expectedReturn, $api->listByProject($projectId));
@@ -50,21 +50,21 @@ public function testListByProjectWithParametersReturnsResponse(): void
         $response = '["API Response"]';
         $expectedReturn = ['API Response'];
 
-        // Create the used mock objects
-        $client = $this->createMock(Client::class);
-        $client->expects($this->once())
-            ->method('requestGet')
-            ->with('/projects/project-slug/issue_categories.json?limit=25&offset=0&0=not-used')
-            ->willReturn(true);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseBody')
-            ->willReturn($response);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseContentType')
-            ->willReturn('application/json');
+        $client = AssertingHttpClient::create(
+            $this,
+            [
+                'GET',
+                '/projects/project-slug/issue_categories.json?limit=25&offset=0&0=not-used',
+                'application/json',
+                '',
+                200,
+                'application/json',
+                $response,
+            ],
+        );
 
         // Create the object under test
-        $api = new IssueCategory($client);
+        $api = IssueCategory::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame($expectedReturn, $api->listByProject($projectId, $parameters));
@@ -76,7 +76,7 @@ public function testListByProjectWithParametersReturnsResponse(): void
     #[DataProviderExternal(TestDataProvider::class, 'getInvalidProjectIdentifiers')]
     public function testListByProjectWithWrongProjectIdentifierThrowsException($projectIdentifier): void
     {
-        $api = new IssueCategory(MockClient::create());
+        $api = IssueCategory::fromHttpClient($this->createStub(HttpClient::class));
 
         $this->expectException(InvalidParameterException::class);
         $this->expectExceptionMessage('Redmine\Api\IssueCategory::listByProject(): Argument #1 ($projectIdentifier) must be of type int or string');
@@ -86,21 +86,21 @@ public function testListByProjectWithWrongProjectIdentifierThrowsException($proj
 
     public function testListByProjectThrowsException(): void
     {
-        // Create the used mock objects
-        $client = $this->createMock(Client::class);
-        $client->expects($this->exactly(1))
-            ->method('requestGet')
-            ->with('/projects/5/issue_categories.json')
-            ->willReturn(true);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseBody')
-            ->willReturn('');
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseContentType')
-            ->willReturn('application/json');
+        $client = AssertingHttpClient::create(
+            $this,
+            [
+                'GET',
+                '/projects/5/issue_categories.json',
+                'application/json',
+                '',
+                200,
+                'application/json',
+                '',
+            ],
+        );
 
         // Create the object under test
-        $api = new IssueCategory($client);
+        $api = IssueCategory::fromHttpClient($client);
 
         $this->expectException(UnexpectedResponseException::class);
         $this->expectExceptionMessage('The Redmine server replied with an unexpected response.');
diff --git a/tests/Unit/Api/IssueCategory/ListNamesByProjectTest.php b/tests/Unit/Api/IssueCategory/ListNamesByProjectTest.php
index e10ffc90..9f7f693b 100644
--- a/tests/Unit/Api/IssueCategory/ListNamesByProjectTest.php
+++ b/tests/Unit/Api/IssueCategory/ListNamesByProjectTest.php
@@ -37,7 +37,7 @@ public function testListNamesByProjectReturnsCorrectResponse($projectIdentifier,
         );
 
         // Create the object under test
-        $api = new IssueCategory($client);
+        $api = IssueCategory::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame($expectedResponse, $api->listNamesByProject($projectIdentifier));
@@ -104,7 +104,7 @@ public function testListNamesByProjectCallsHttpClientOnlyOnce(): void
         );
 
         // Create the object under test
-        $api = new IssueCategory($client);
+        $api = IssueCategory::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame([1 => 'IssueCategory 1'], $api->listNamesByProject(5));
@@ -118,7 +118,7 @@ public function testListNamesByProjectCallsHttpClientOnlyOnce(): void
     #[DataProviderExternal(TestDataProvider::class, 'getInvalidProjectIdentifiers')]
     public function testListNamesByProjectWithWrongProjectIdentifierThrowsException($projectIdentifier): void
     {
-        $api = new IssueCategory($this->createStub(HttpClient::class));
+        $api = IssueCategory::fromHttpClient($this->createStub(HttpClient::class));
 
         $this->expectException(InvalidParameterException::class);
         $this->expectExceptionMessage('Redmine\Api\IssueCategory::listNamesByProject(): Argument #1 ($projectIdentifier) must be of type int or string');
diff --git a/tests/Unit/Api/IssueCategory/RemoveTest.php b/tests/Unit/Api/IssueCategory/RemoveTest.php
index 42bfad30..d577e69b 100644
--- a/tests/Unit/Api/IssueCategory/RemoveTest.php
+++ b/tests/Unit/Api/IssueCategory/RemoveTest.php
@@ -31,7 +31,7 @@ public function testRemoveReturnsCorrectResponse(int $issueId, array $params, st
         );
 
         // Create the object under test
-        $api = new IssueCategory($client);
+        $api = IssueCategory::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame($response, $api->remove($issueId, $params));
diff --git a/tests/Unit/Api/IssueCategory/ShowTest.php b/tests/Unit/Api/IssueCategory/ShowTest.php
index 2bef557c..1514591c 100644
--- a/tests/Unit/Api/IssueCategory/ShowTest.php
+++ b/tests/Unit/Api/IssueCategory/ShowTest.php
@@ -31,7 +31,7 @@ public function testShowReturnsCorrectResponse($id, string $expectedPath, string
         );
 
         // Create the object under test
-        $api = new IssueCategory($client);
+        $api = IssueCategory::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame($expectedReturn, $api->show($id));
diff --git a/tests/Unit/Api/IssueCategory/UpdateTest.php b/tests/Unit/Api/IssueCategory/UpdateTest.php
index fc8f0d95..f8f677b8 100644
--- a/tests/Unit/Api/IssueCategory/UpdateTest.php
+++ b/tests/Unit/Api/IssueCategory/UpdateTest.php
@@ -33,7 +33,7 @@ public function testUpdateReturnsCorrectResponse(int $id, array $parameters, str
         );
 
         // Create the object under test
-        $api = new IssueCategory($client);
+        $api = IssueCategory::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame('', $api->update($id, $parameters));
diff --git a/tests/Unit/Api/IssueCategoryTest.php b/tests/Unit/Api/IssueCategoryTest.php
index a37e9c50..bbf8a195 100644
--- a/tests/Unit/Api/IssueCategoryTest.php
+++ b/tests/Unit/Api/IssueCategoryTest.php
@@ -6,8 +6,8 @@
 use PHPUnit\Framework\Attributes\DataProvider;
 use PHPUnit\Framework\TestCase;
 use Redmine\Api\IssueCategory;
-use Redmine\Client\Client;
-use Redmine\Tests\Fixtures\MockClient;
+use Redmine\Http\HttpClient;
+use Redmine\Tests\Fixtures\AssertingHttpClient;
 
 /**
  * @author     Malte Gerth <mail@malte-gerth.de>
@@ -15,12 +15,50 @@
 #[CoversClass(IssueCategory::class)]
 class IssueCategoryTest extends TestCase
 {
+    public function testExtendingTheClassTriggersDeprecationWarning(): void
+    {
+        // PHPUnit 10 compatible way to test trigger_error().
+        set_error_handler(
+            function ($errno, $errstr): bool {
+                $this->assertSame(
+                    'Class `Redmine\Api\IssueCategory` will declared as final in v3.0.0, stop extending it.',
+                    $errstr,
+                );
+
+                restore_error_handler();
+                return true;
+            },
+            E_USER_DEPRECATED,
+        );
+
+        new class ($this->createStub(HttpClient::class)) extends IssueCategory {};
+    }
+
+    public function testConstructorTriggersDeprecationWarning(): void
+    {
+        // PHPUnit 10 compatible way to test trigger_error().
+        set_error_handler(
+            function ($errno, $errstr): bool {
+                $this->assertSame(
+                    'Method `Redmine\Api\IssueCategory::__construct()` is deprecated since v2.9.0 and will declared as private in v3.0.0, use `Redmine\Api\IssueCategory::fromHttpClient()` instead.',
+                    $errstr,
+                );
+
+                restore_error_handler();
+                return true;
+            },
+            E_USER_DEPRECATED,
+        );
+
+        new IssueCategory($this->createStub(HttpClient::class));
+    }
+
     /**
      * Test all().
      */
     public function testAllTriggersDeprecationWarning(): void
     {
-        $api = new IssueCategory(MockClient::create());
+        $api = IssueCategory::fromHttpClient($this->createStub(HttpClient::class));
 
         // PHPUnit 10 compatible way to test trigger_error().
         set_error_handler(
@@ -50,21 +88,21 @@ public function testAllReturnsClientGetResponseWithProject(string $response, str
         // Test values
         $projectId = 5;
 
-        // Create the used mock objects
-        $client = $this->createMock(Client::class);
-        $client->expects($this->exactly(1))
-            ->method('requestGet')
-            ->with('/projects/5/issue_categories.json')
-            ->willReturn(true);
-        $client->expects($this->atLeast(1))
-            ->method('getLastResponseBody')
-            ->willReturn($response);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseContentType')
-            ->willReturn($responseType);
+        $client = AssertingHttpClient::create(
+            $this,
+            [
+                'GET',
+                '/projects/5/issue_categories.json',
+                'application/json',
+                '',
+                200,
+                $responseType,
+                $response,
+            ],
+        );
 
         // Create the object under test
-        $api = new IssueCategory($client);
+        $api = IssueCategory::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame($expectedResponse, $api->all($projectId));
@@ -90,26 +128,21 @@ public function testAllReturnsClientGetResponseWithParametersAndProject(): void
         $response = '["API Response"]';
         $expectedReturn = ['API Response'];
 
-        // Create the used mock objects
-        $client = $this->createMock(Client::class);
-        $client->expects($this->once())
-            ->method('requestGet')
-            ->with(
-                $this->logicalAnd(
-                    $this->stringStartsWith('/projects/5/issue_categories.json'),
-                    $this->stringContains('not-used'),
-                ),
-            )
-            ->willReturn(true);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseBody')
-            ->willReturn($response);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseContentType')
-            ->willReturn('application/json');
+        $client = AssertingHttpClient::create(
+            $this,
+            [
+                'GET',
+                '/projects/5/issue_categories.json?limit=25&offset=0&0=not-used',
+                'application/json',
+                '',
+                200,
+                'application/json',
+                $response,
+            ],
+        );
 
         // Create the object under test
-        $api = new IssueCategory($client);
+        $api = IssueCategory::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame($expectedReturn, $api->all($projectId, $parameters));
@@ -127,23 +160,21 @@ public function testListingReturnsNameIdArray(): void
             'IssueCategory 5' => 5,
         ];
 
-        // Create the used mock objects
-        $client = $this->createMock(Client::class);
-        $client->expects($this->once())
-            ->method('requestGet')
-            ->with(
-                $this->stringStartsWith('/projects/5/issue_categories'),
-            )
-            ->willReturn(true);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseBody')
-            ->willReturn($response);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseContentType')
-            ->willReturn('application/json');
+        $client = AssertingHttpClient::create(
+            $this,
+            [
+                'GET',
+                '/projects/5/issue_categories.json',
+                'application/json',
+                '',
+                200,
+                'application/json',
+                $response,
+            ],
+        );
 
         // Create the object under test
-        $api = new IssueCategory($client);
+        $api = IssueCategory::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame($expectedReturn, $api->listing(5));
@@ -161,23 +192,21 @@ public function testListingCallsGetOnlyTheFirstTime(): void
             'IssueCategory 5' => 5,
         ];
 
-        // Create the used mock objects
-        $client = $this->createMock(Client::class);
-        $client->expects($this->once())
-            ->method('requestGet')
-            ->with(
-                $this->stringStartsWith('/projects/5/issue_categories'),
-            )
-            ->willReturn(true);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseBody')
-            ->willReturn($response);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseContentType')
-            ->willReturn('application/json');
+        $client = AssertingHttpClient::create(
+            $this,
+            [
+                'GET',
+                '/projects/5/issue_categories.json',
+                'application/json',
+                '',
+                200,
+                'application/json',
+                $response,
+            ],
+        );
 
         // Create the object under test
-        $api = new IssueCategory($client);
+        $api = IssueCategory::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame($expectedReturn, $api->listing(5));
@@ -196,23 +225,30 @@ public function testListingCallsGetEveryTimeWithForceUpdate(): void
             'IssueCategory 5' => 5,
         ];
 
-        // Create the used mock objects
-        $client = $this->createMock(Client::class);
-        $client->expects($this->exactly(2))
-            ->method('requestGet')
-            ->with(
-                $this->stringStartsWith('/projects/5/issue_categories'),
-            )
-            ->willReturn(true);
-        $client->expects($this->exactly(2))
-            ->method('getLastResponseBody')
-            ->willReturn($response);
-        $client->expects($this->exactly(2))
-            ->method('getLastResponseContentType')
-            ->willReturn('application/json');
+        $client = AssertingHttpClient::create(
+            $this,
+            [
+                'GET',
+                '/projects/5/issue_categories.json',
+                'application/json',
+                '',
+                200,
+                'application/json',
+                $response,
+            ],
+            [
+                'GET',
+                '/projects/5/issue_categories.json',
+                'application/json',
+                '',
+                200,
+                'application/json',
+                $response,
+            ],
+        );
 
         // Create the object under test
-        $api = new IssueCategory($client);
+        $api = IssueCategory::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame($expectedReturn, $api->listing(5, true));
@@ -224,15 +260,22 @@ public function testListingCallsGetEveryTimeWithForceUpdate(): void
      */
     public function testListingTriggersDeprecationWarning(): void
     {
-        $client = $this->createStub(Client::class);
-        $client->method('requestGet')
-            ->willReturn(true);
-        $client->method('getLastResponseBody')
-            ->willReturn('{"issue_categories":[{"id":1,"name":"IssueCategory 1"},{"id":5,"name":"IssueCategory 5"}]}');
-        $client->method('getLastResponseContentType')
-            ->willReturn('application/json');
+        $response = '{"issue_categories":[{"id":1,"name":"IssueCategory 1"},{"id":5,"name":"IssueCategory 5"}]}';
+
+        $client = AssertingHttpClient::create(
+            $this,
+            [
+                'GET',
+                '/projects/5/issue_categories.json',
+                'application/json',
+                '',
+                200,
+                'application/json',
+                $response,
+            ],
+        );
 
-        $api = new IssueCategory($client);
+        $api = IssueCategory::fromHttpClient($client);
 
         // PHPUnit 10 compatible way to test trigger_error().
         set_error_handler(
@@ -259,23 +302,21 @@ public function testGetIdByNameMakesGetRequest(): void
         // Test values
         $response = '{"issue_categories":[{"id":5,"name":"IssueCategory 5"}]}';
 
-        // Create the used mock objects
-        $client = $this->createMock(Client::class);
-        $client->expects($this->once())
-            ->method('requestGet')
-            ->with(
-                $this->stringStartsWith('/projects/5/issue_categories.json'),
-            )
-            ->willReturn(true);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseBody')
-            ->willReturn($response);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseContentType')
-            ->willReturn('application/json');
+        $client = AssertingHttpClient::create(
+            $this,
+            [
+                'GET',
+                '/projects/5/issue_categories.json',
+                'application/json',
+                '',
+                200,
+                'application/json',
+                $response,
+            ],
+        );
 
         // Create the object under test
-        $api = new IssueCategory($client);
+        $api = IssueCategory::fromHttpClient($client);
 
         // Perform the tests
         $this->assertFalse($api->getIdByName(5, 'IssueCategory 1'));
@@ -284,15 +325,22 @@ public function testGetIdByNameMakesGetRequest(): void
 
     public function testGetIdByNameTriggersDeprecationWarning(): void
     {
-        $client = $this->createStub(Client::class);
-        $client->method('requestGet')
-            ->willReturn(true);
-        $client->method('getLastResponseBody')
-            ->willReturn('{"issue_categories":[{"id":1,"name":"IssueCategory 1"},{"id":5,"name":"IssueCategory 5"}]}');
-        $client->method('getLastResponseContentType')
-            ->willReturn('application/json');
-
-        $api = new IssueCategory($client);
+        $response = '{"issue_categories":[{"id":1,"name":"IssueCategory 1"},{"id":5,"name":"IssueCategory 5"}]}';
+
+        $client = AssertingHttpClient::create(
+            $this,
+            [
+                'GET',
+                '/projects/5/issue_categories.json',
+                'application/json',
+                '',
+                200,
+                'application/json',
+                $response,
+            ],
+        );
+
+        $api = IssueCategory::fromHttpClient($client);
 
         // PHPUnit 10 compatible way to test trigger_error().
         set_error_handler(
diff --git a/tests/Unit/Api/IssuePriority/FromHttpClientTest.php b/tests/Unit/Api/IssuePriority/FromHttpClientTest.php
new file mode 100644
index 00000000..4748ecaa
--- /dev/null
+++ b/tests/Unit/Api/IssuePriority/FromHttpClientTest.php
@@ -0,0 +1,21 @@
+<?php
+
+namespace Redmine\Tests\Unit\Api\IssuePriority;
+
+use PHPUnit\Framework\Attributes\CoversClass;
+use PHPUnit\Framework\TestCase;
+use Redmine\Api\IssuePriority;
+use Redmine\Http\HttpClient;
+
+#[CoversClass(IssuePriority::class)]
+class FromHttpClientTest extends TestCase
+{
+    public function testReturnsCorrectObject(): void
+    {
+        $httpClient = $this->createStub(HttpClient::class);
+
+        $api = IssuePriority::fromHttpClient($httpClient);
+
+        $this->assertInstanceOf(IssuePriority::class, $api);
+    }
+}
diff --git a/tests/Unit/Api/IssuePriority/ListTest.php b/tests/Unit/Api/IssuePriority/ListTest.php
index 81171687..32645172 100644
--- a/tests/Unit/Api/IssuePriority/ListTest.php
+++ b/tests/Unit/Api/IssuePriority/ListTest.php
@@ -7,6 +7,7 @@
 use Redmine\Api\IssuePriority;
 use Redmine\Client\Client;
 use Redmine\Exception\UnexpectedResponseException;
+use Redmine\Tests\Fixtures\AssertingHttpClient;
 
 #[CoversClass(IssuePriority::class)]
 class ListTest extends TestCase
@@ -17,21 +18,21 @@ public function testListWithoutParametersReturnsResponse(): void
         $response = '["API Response"]';
         $expectedReturn = ['API Response'];
 
-        // Create the used mock objects
-        $client = $this->createMock(Client::class);
-        $client->expects($this->once())
-            ->method('requestGet')
-            ->with('/enumerations/issue_priorities.json')
-            ->willReturn(true);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseBody')
-            ->willReturn($response);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseContentType')
-            ->willReturn('application/json');
+        $client = AssertingHttpClient::create(
+            $this,
+            [
+                'GET',
+                '/enumerations/issue_priorities.json',
+                'application/json',
+                '',
+                200,
+                'application/json',
+                $response,
+            ],
+        );
 
         // Create the object under test
-        $api = new IssuePriority($client);
+        $api = IssuePriority::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame($expectedReturn, $api->list());
@@ -44,21 +45,21 @@ public function testListWithParametersReturnsResponse(): void
         $response = '["API Response"]';
         $expectedReturn = ['API Response'];
 
-        // Create the used mock objects
-        $client = $this->createMock(Client::class);
-        $client->expects($this->once())
-            ->method('requestGet')
-            ->with('/enumerations/issue_priorities.json?limit=25&offset=0&0=not-used')
-            ->willReturn(true);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseBody')
-            ->willReturn($response);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseContentType')
-            ->willReturn('application/json');
+        $client = AssertingHttpClient::create(
+            $this,
+            [
+                'GET',
+                '/enumerations/issue_priorities.json?limit=25&offset=0&0=not-used',
+                'application/json',
+                '',
+                200,
+                'application/json',
+                $response,
+            ],
+        );
 
         // Create the object under test
-        $api = new IssuePriority($client);
+        $api = IssuePriority::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame($expectedReturn, $api->list($allParameters));
@@ -66,21 +67,21 @@ public function testListWithParametersReturnsResponse(): void
 
     public function testListThrowsException(): void
     {
-        // Create the used mock objects
-        $client = $this->createMock(Client::class);
-        $client->expects($this->exactly(1))
-            ->method('requestGet')
-            ->with('/enumerations/issue_priorities.json')
-            ->willReturn(true);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseBody')
-            ->willReturn('');
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseContentType')
-            ->willReturn('application/json');
+        $client = AssertingHttpClient::create(
+            $this,
+            [
+                'GET',
+                '/enumerations/issue_priorities.json',
+                'application/json',
+                '',
+                200,
+                'application/json',
+                '',
+            ],
+        );
 
         // Create the object under test
-        $api = new IssuePriority($client);
+        $api = IssuePriority::fromHttpClient($client);
 
         $this->expectException(UnexpectedResponseException::class);
         $this->expectExceptionMessage('The Redmine server replied with an unexpected response.');
diff --git a/tests/Unit/Api/IssuePriorityTest.php b/tests/Unit/Api/IssuePriorityTest.php
index 7363db9a..8cc73164 100644
--- a/tests/Unit/Api/IssuePriorityTest.php
+++ b/tests/Unit/Api/IssuePriorityTest.php
@@ -7,6 +7,8 @@
 use PHPUnit\Framework\TestCase;
 use Redmine\Api\IssuePriority;
 use Redmine\Client\Client;
+use Redmine\Http\HttpClient;
+use Redmine\Tests\Fixtures\AssertingHttpClient;
 use Redmine\Tests\Fixtures\MockClient;
 
 /**
@@ -15,12 +17,50 @@
 #[CoversClass(IssuePriority::class)]
 class IssuePriorityTest extends TestCase
 {
+    public function testExtendingTheClassTriggersDeprecationWarning(): void
+    {
+        // PHPUnit 10 compatible way to test trigger_error().
+        set_error_handler(
+            function ($errno, $errstr): bool {
+                $this->assertSame(
+                    'Class `Redmine\Api\IssuePriority` will declared as final in v3.0.0, stop extending it.',
+                    $errstr,
+                );
+
+                restore_error_handler();
+                return true;
+            },
+            E_USER_DEPRECATED,
+        );
+
+        new class ($this->createStub(HttpClient::class)) extends IssuePriority {};
+    }
+
+    public function testConstructorTriggersDeprecationWarning(): void
+    {
+        // PHPUnit 10 compatible way to test trigger_error().
+        set_error_handler(
+            function ($errno, $errstr): bool {
+                $this->assertSame(
+                    'Method `Redmine\Api\IssuePriority::__construct()` is deprecated since v2.9.0 and will declared as private in v3.0.0, use `Redmine\Api\IssuePriority::fromHttpClient()` instead.',
+                    $errstr,
+                );
+
+                restore_error_handler();
+                return true;
+            },
+            E_USER_DEPRECATED,
+        );
+
+        new IssuePriority($this->createStub(HttpClient::class));
+    }
+
     /**
      * Test all().
      */
     public function testAllTriggersDeprecationWarning(): void
     {
-        $api = new IssuePriority(MockClient::create());
+        $api = IssuePriority::fromHttpClient($this->createStub(HttpClient::class));
 
         // PHPUnit 10 compatible way to test trigger_error().
         set_error_handler(
@@ -47,21 +87,21 @@ function ($errno, $errstr): bool {
     #[DataProvider('getAllData')]
     public function testAllReturnsClientGetResponse(string $response, string $responseType, $expectedResponse): void
     {
-        // Create the used mock objects
-        $client = $this->createMock(Client::class);
-        $client->expects($this->exactly(1))
-            ->method('requestGet')
-            ->with('/enumerations/issue_priorities.json')
-            ->willReturn(true);
-        $client->expects($this->atLeast(1))
-            ->method('getLastResponseBody')
-            ->willReturn($response);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseContentType')
-            ->willReturn($responseType);
+        $client = AssertingHttpClient::create(
+            $this,
+            [
+                'GET',
+                '/enumerations/issue_priorities.json',
+                'application/json',
+                '',
+                200,
+                $responseType,
+                $response,
+            ],
+        );
 
         // Create the object under test
-        $api = new IssuePriority($client);
+        $api = IssuePriority::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame($expectedResponse, $api->all());
@@ -86,23 +126,21 @@ public function testAllReturnsClientGetResponseWithParameters(): void
         $response = '["API Response"]';
         $expectedReturn = ['API Response'];
 
-        // Create the used mock objects
-        $client = $this->createMock(Client::class);
-        $client->expects($this->once())
-            ->method('requestGet')
-            ->with(
-                $this->stringContains('not-used'),
-            )
-            ->willReturn(true);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseBody')
-            ->willReturn($response);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseContentType')
-            ->willReturn('application/json');
+        $client = AssertingHttpClient::create(
+            $this,
+            [
+                'GET',
+                '/enumerations/issue_priorities.json?limit=25&offset=0&0=not-used',
+                'application/json',
+                '',
+                200,
+                'application/json',
+                $response,
+            ],
+        );
 
         // Create the object under test
-        $api = new IssuePriority($client);
+        $api = IssuePriority::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame($expectedReturn, $api->all($allParameters));
diff --git a/tests/Unit/Api/IssueRelation/CreateTest.php b/tests/Unit/Api/IssueRelation/CreateTest.php
index 8b486e08..d6dde0ee 100644
--- a/tests/Unit/Api/IssueRelation/CreateTest.php
+++ b/tests/Unit/Api/IssueRelation/CreateTest.php
@@ -34,7 +34,7 @@ public function testCreateReturnsCorrectResponse(int $issueId, array $parameters
         );
 
         // Create the object under test
-        $api = new IssueRelation($client);
+        $api = IssueRelation::fromHttpClient($client);
 
         // Perform the tests
         $return = $api->create($issueId, $parameters);
@@ -74,7 +74,7 @@ public function testCreateThrowsExceptionIfResponseContainsEmptyString(): void
         );
 
         // Create the object under test
-        $api = new IssueRelation($client);
+        $api = IssueRelation::fromHttpClient($client);
 
         $this->expectException(SerializerException::class);
         $this->expectExceptionMessage('Catched error "Syntax error" while decoding JSON: ');
@@ -89,7 +89,7 @@ public function testCreateThrowsExceptionWithEmptyParameters(): void
         $client = $this->createStub(HttpClient::class);
 
         // Create the object under test
-        $api = new IssueRelation($client);
+        $api = IssueRelation::fromHttpClient($client);
 
         $this->expectException(MissingParameterException::class);
         $this->expectExceptionMessage('Theses parameters are mandatory: `issue_to_id`');
@@ -108,7 +108,7 @@ public function testCreateThrowsExceptionIfMandatoyParametersAreMissing(array $p
         $client = $this->createStub(HttpClient::class);
 
         // Create the object under test
-        $api = new IssueRelation($client);
+        $api = IssueRelation::fromHttpClient($client);
 
         $this->expectException(MissingParameterException::class);
         $this->expectExceptionMessage('Theses parameters are mandatory: `issue_to_id`');
diff --git a/tests/Unit/Api/IssueRelation/FromHttpClientTest.php b/tests/Unit/Api/IssueRelation/FromHttpClientTest.php
new file mode 100644
index 00000000..a8d0c9d1
--- /dev/null
+++ b/tests/Unit/Api/IssueRelation/FromHttpClientTest.php
@@ -0,0 +1,21 @@
+<?php
+
+namespace Redmine\Tests\Unit\Api\IssueRelation;
+
+use PHPUnit\Framework\Attributes\CoversClass;
+use PHPUnit\Framework\TestCase;
+use Redmine\Api\IssueRelation;
+use Redmine\Http\HttpClient;
+
+#[CoversClass(IssueRelation::class)]
+class FromHttpClientTest extends TestCase
+{
+    public function testReturnsCorrectObject(): void
+    {
+        $httpClient = $this->createStub(HttpClient::class);
+
+        $api = IssueRelation::fromHttpClient($httpClient);
+
+        $this->assertInstanceOf(IssueRelation::class, $api);
+    }
+}
diff --git a/tests/Unit/Api/IssueRelation/ListByIssueIdTest.php b/tests/Unit/Api/IssueRelation/ListByIssueIdTest.php
index ea06fa3a..c849159d 100644
--- a/tests/Unit/Api/IssueRelation/ListByIssueIdTest.php
+++ b/tests/Unit/Api/IssueRelation/ListByIssueIdTest.php
@@ -7,6 +7,7 @@
 use Redmine\Api\IssueRelation;
 use Redmine\Client\Client;
 use Redmine\Exception\UnexpectedResponseException;
+use Redmine\Tests\Fixtures\AssertingHttpClient;
 
 #[CoversClass(IssueRelation::class)]
 class ListByIssueIdTest extends TestCase
@@ -17,21 +18,21 @@ public function testListByIssueIdWithoutParametersReturnsResponse(): void
         $response = '["API Response"]';
         $expectedReturn = ['API Response'];
 
-        // Create the used mock objects
-        $client = $this->createMock(Client::class);
-        $client->expects($this->once())
-            ->method('requestGet')
-            ->with('/issues/5/relations.json')
-            ->willReturn(true);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseBody')
-            ->willReturn($response);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseContentType')
-            ->willReturn('application/json');
+        $client = AssertingHttpClient::create(
+            $this,
+            [
+                'GET',
+                '/issues/5/relations.json',
+                'application/json',
+                '',
+                200,
+                'application/json',
+                $response,
+            ],
+        );
 
         // Create the object under test
-        $api = new IssueRelation($client);
+        $api = IssueRelation::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame($expectedReturn, $api->listByIssueId(5));
@@ -44,21 +45,21 @@ public function testListByIssueIdWithParametersReturnsResponse(): void
         $response = '["API Response"]';
         $expectedReturn = ['API Response'];
 
-        // Create the used mock objects
-        $client = $this->createMock(Client::class);
-        $client->expects($this->once())
-            ->method('requestGet')
-            ->with('/issues/5/relations.json?limit=25&offset=0&0=not-used')
-            ->willReturn(true);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseBody')
-            ->willReturn($response);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseContentType')
-            ->willReturn('application/json');
+        $client = AssertingHttpClient::create(
+            $this,
+            [
+                'GET',
+                '/issues/5/relations.json?limit=25&offset=0&0=not-used',
+                'application/json',
+                '',
+                200,
+                'application/json',
+                $response,
+            ],
+        );
 
         // Create the object under test
-        $api = new IssueRelation($client);
+        $api = IssueRelation::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame($expectedReturn, $api->listByIssueId(5, $parameters));
@@ -66,21 +67,21 @@ public function testListByIssueIdWithParametersReturnsResponse(): void
 
     public function testListByIssueIdThrowsException(): void
     {
-        // Create the used mock objects
-        $client = $this->createMock(Client::class);
-        $client->expects($this->exactly(1))
-            ->method('requestGet')
-            ->with('/issues/5/relations.json')
-            ->willReturn(true);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseBody')
-            ->willReturn('');
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseContentType')
-            ->willReturn('application/json');
+        $client = AssertingHttpClient::create(
+            $this,
+            [
+                'GET',
+                '/issues/5/relations.json',
+                'application/json',
+                '',
+                200,
+                'application/json',
+                '',
+            ],
+        );
 
         // Create the object under test
-        $api = new IssueRelation($client);
+        $api = IssueRelation::fromHttpClient($client);
 
         $this->expectException(UnexpectedResponseException::class);
         $this->expectExceptionMessage('The Redmine server replied with an unexpected response.');
diff --git a/tests/Unit/Api/IssueRelation/RemoveTest.php b/tests/Unit/Api/IssueRelation/RemoveTest.php
index 0068abfa..513c2a4b 100644
--- a/tests/Unit/Api/IssueRelation/RemoveTest.php
+++ b/tests/Unit/Api/IssueRelation/RemoveTest.php
@@ -31,7 +31,7 @@ public function testRemoveReturnsCorrectResponse(int $issueId, string $expectedP
         );
 
         // Create the object under test
-        $api = new IssueRelation($client);
+        $api = IssueRelation::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame($response, $api->remove($issueId));
diff --git a/tests/Unit/Api/IssueRelation/ShowTest.php b/tests/Unit/Api/IssueRelation/ShowTest.php
index b28b2091..5bd6de93 100644
--- a/tests/Unit/Api/IssueRelation/ShowTest.php
+++ b/tests/Unit/Api/IssueRelation/ShowTest.php
@@ -31,7 +31,7 @@ public function testShowReturnsCorrectResponse($id, string $expectedPath, string
         );
 
         // Create the object under test
-        $api = new IssueRelation($client);
+        $api = IssueRelation::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame($expectedReturn, $api->show($id));
diff --git a/tests/Unit/Api/IssueRelationTest.php b/tests/Unit/Api/IssueRelationTest.php
index f744ce29..0bc7313e 100644
--- a/tests/Unit/Api/IssueRelationTest.php
+++ b/tests/Unit/Api/IssueRelationTest.php
@@ -7,6 +7,8 @@
 use PHPUnit\Framework\TestCase;
 use Redmine\Api\IssueRelation;
 use Redmine\Client\Client;
+use Redmine\Http\HttpClient;
+use Redmine\Tests\Fixtures\AssertingHttpClient;
 use Redmine\Tests\Fixtures\MockClient;
 
 /**
@@ -15,12 +17,50 @@
 #[CoversClass(IssueRelation::class)]
 class IssueRelationTest extends TestCase
 {
+    public function testExtendingTheClassTriggersDeprecationWarning(): void
+    {
+        // PHPUnit 10 compatible way to test trigger_error().
+        set_error_handler(
+            function ($errno, $errstr): bool {
+                $this->assertSame(
+                    'Class `Redmine\Api\IssueRelation` will declared as final in v3.0.0, stop extending it.',
+                    $errstr,
+                );
+
+                restore_error_handler();
+                return true;
+            },
+            E_USER_DEPRECATED,
+        );
+
+        new class ($this->createStub(HttpClient::class)) extends IssueRelation {};
+    }
+
+    public function testConstructorTriggersDeprecationWarning(): void
+    {
+        // PHPUnit 10 compatible way to test trigger_error().
+        set_error_handler(
+            function ($errno, $errstr): bool {
+                $this->assertSame(
+                    'Method `Redmine\Api\IssueRelation::__construct()` is deprecated since v2.9.0 and will declared as private in v3.0.0, use `Redmine\Api\IssueRelation::fromHttpClient()` instead.',
+                    $errstr,
+                );
+
+                restore_error_handler();
+                return true;
+            },
+            E_USER_DEPRECATED,
+        );
+
+        new IssueRelation($this->createStub(HttpClient::class));
+    }
+
     /**
      * Test all().
      */
     public function testAllTriggersDeprecationWarning(): void
     {
-        $api = new IssueRelation(MockClient::create());
+        $api = IssueRelation::fromHttpClient($this->createStub(HttpClient::class));
 
         // PHPUnit 10 compatible way to test trigger_error().
         set_error_handler(
@@ -47,21 +87,21 @@ function ($errno, $errstr): bool {
     #[DataProvider('getAllData')]
     public function testAllReturnsClientGetResponseWithProject(string $response, string $responseType, $expectedResponse): void
     {
-        // Create the used mock objects
-        $client = $this->createMock(Client::class);
-        $client->expects($this->exactly(1))
-            ->method('requestGet')
-            ->with('/issues/5/relations.json')
-            ->willReturn(true);
-        $client->expects($this->atLeast(1))
-            ->method('getLastResponseBody')
-            ->willReturn($response);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseContentType')
-            ->willReturn($responseType);
+        $client = AssertingHttpClient::create(
+            $this,
+            [
+                'GET',
+                '/issues/5/relations.json',
+                'application/json',
+                '',
+                200,
+                $responseType,
+                $response,
+            ],
+        );
 
         // Create the object under test
-        $api = new IssueRelation($client);
+        $api = IssueRelation::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame($expectedResponse, $api->all(5));
@@ -86,26 +126,21 @@ public function testAllReturnsClientGetResponseWithParametersAndProject(): void
         $response = '["API Response"]';
         $expectedReturn = ['API Response'];
 
-        // Create the used mock objects
-        $client = $this->createMock(Client::class);
-        $client->expects($this->once())
-            ->method('requestGet')
-            ->with(
-                $this->logicalAnd(
-                    $this->stringStartsWith('/issues/5/relations.json'),
-                    $this->stringContains('not-used'),
-                ),
-            )
-            ->willReturn(true);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseBody')
-            ->willReturn($response);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseContentType')
-            ->willReturn('application/json');
+        $client = AssertingHttpClient::create(
+            $this,
+            [
+                'GET',
+                '/issues/5/relations.json?limit=25&offset=0&0=not-used',
+                'application/json',
+                '',
+                200,
+                'application/json',
+                $response,
+            ],
+        );
 
         // Create the object under test
-        $api = new IssueRelation($client);
+        $api = IssueRelation::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame($expectedReturn, $api->all(5, $parameters));
diff --git a/tests/Unit/Api/IssueStatus/FromHttpClientTest.php b/tests/Unit/Api/IssueStatus/FromHttpClientTest.php
new file mode 100644
index 00000000..bf639ef7
--- /dev/null
+++ b/tests/Unit/Api/IssueStatus/FromHttpClientTest.php
@@ -0,0 +1,21 @@
+<?php
+
+namespace Redmine\Tests\Unit\Api\IssueStatus;
+
+use PHPUnit\Framework\Attributes\CoversClass;
+use PHPUnit\Framework\TestCase;
+use Redmine\Api\IssueStatus;
+use Redmine\Http\HttpClient;
+
+#[CoversClass(IssueStatus::class)]
+class FromHttpClientTest extends TestCase
+{
+    public function testReturnsCorrectObject(): void
+    {
+        $httpClient = $this->createStub(HttpClient::class);
+
+        $api = IssueStatus::fromHttpClient($httpClient);
+
+        $this->assertInstanceOf(IssueStatus::class, $api);
+    }
+}
diff --git a/tests/Unit/Api/IssueStatus/ListNamesTest.php b/tests/Unit/Api/IssueStatus/ListNamesTest.php
index 98789e13..771808cd 100644
--- a/tests/Unit/Api/IssueStatus/ListNamesTest.php
+++ b/tests/Unit/Api/IssueStatus/ListNamesTest.php
@@ -33,7 +33,7 @@ public function testListNamesReturnsCorrectResponse(string $expectedPath, int $r
         );
 
         // Create the object under test
-        $api = new IssueStatus($client);
+        $api = IssueStatus::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame($expectedResponse, $api->listNames());
@@ -98,7 +98,7 @@ public function testListNamesCallsHttpClientOnlyOnce(): void
         );
 
         // Create the object under test
-        $api = new IssueStatus($client);
+        $api = IssueStatus::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame([1 => 'IssueStatus 1'], $api->listNames());
diff --git a/tests/Unit/Api/IssueStatus/ListTest.php b/tests/Unit/Api/IssueStatus/ListTest.php
index 03b1d75e..fe174634 100644
--- a/tests/Unit/Api/IssueStatus/ListTest.php
+++ b/tests/Unit/Api/IssueStatus/ListTest.php
@@ -5,8 +5,8 @@
 use PHPUnit\Framework\Attributes\CoversClass;
 use PHPUnit\Framework\TestCase;
 use Redmine\Api\IssueStatus;
-use Redmine\Client\Client;
 use Redmine\Exception\UnexpectedResponseException;
+use Redmine\Tests\Fixtures\AssertingHttpClient;
 
 #[CoversClass(IssueStatus::class)]
 class ListTest extends TestCase
@@ -17,21 +17,21 @@ public function testListWithoutParametersReturnsResponse(): void
         $response = '["API Response"]';
         $expectedReturn = ['API Response'];
 
-        // Create the used mock objects
-        $client = $this->createMock(Client::class);
-        $client->expects($this->once())
-            ->method('requestGet')
-            ->with('/issue_statuses.json')
-            ->willReturn(true);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseBody')
-            ->willReturn($response);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseContentType')
-            ->willReturn('application/json');
+        $client = AssertingHttpClient::create(
+            $this,
+            [
+                'GET',
+                '/issue_statuses.json',
+                'application/json',
+                '',
+                200,
+                'application/json',
+                $response,
+            ],
+        );
 
         // Create the object under test
-        $api = new IssueStatus($client);
+        $api = IssueStatus::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame($expectedReturn, $api->list());
@@ -44,21 +44,21 @@ public function testListWithParametersReturnsResponse(): void
         $response = '["API Response"]';
         $expectedReturn = ['API Response'];
 
-        // Create the used mock objects
-        $client = $this->createMock(Client::class);
-        $client->expects($this->once())
-            ->method('requestGet')
-            ->with('/issue_statuses.json?limit=25&offset=0&0=not-used')
-            ->willReturn(true);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseBody')
-            ->willReturn($response);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseContentType')
-            ->willReturn('application/json');
+        $client = AssertingHttpClient::create(
+            $this,
+            [
+                'GET',
+                '/issue_statuses.json?limit=25&offset=0&0=not-used',
+                'application/json',
+                '',
+                200,
+                'application/json',
+                $response,
+            ],
+        );
 
         // Create the object under test
-        $api = new IssueStatus($client);
+        $api = IssueStatus::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame($expectedReturn, $api->list($parameters));
@@ -66,21 +66,23 @@ public function testListWithParametersReturnsResponse(): void
 
     public function testListThrowsException(): void
     {
-        // Create the used mock objects
-        $client = $this->createMock(Client::class);
-        $client->expects($this->exactly(1))
-            ->method('requestGet')
-            ->with('/issue_statuses.json')
-            ->willReturn(true);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseBody')
-            ->willReturn('');
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseContentType')
-            ->willReturn('application/json');
+        $response = '';
+
+        $client = AssertingHttpClient::create(
+            $this,
+            [
+                'GET',
+                '/issue_statuses.json',
+                'application/json',
+                '',
+                200,
+                'application/json',
+                $response,
+            ],
+        );
 
         // Create the object under test
-        $api = new IssueStatus($client);
+        $api = IssueStatus::fromHttpClient($client);
 
         $this->expectException(UnexpectedResponseException::class);
         $this->expectExceptionMessage('The Redmine server replied with an unexpected response.');
diff --git a/tests/Unit/Api/IssueStatusTest.php b/tests/Unit/Api/IssueStatusTest.php
index 4bd64210..2e7eb5fa 100644
--- a/tests/Unit/Api/IssueStatusTest.php
+++ b/tests/Unit/Api/IssueStatusTest.php
@@ -6,8 +6,8 @@
 use PHPUnit\Framework\Attributes\DataProvider;
 use PHPUnit\Framework\TestCase;
 use Redmine\Api\IssueStatus;
-use Redmine\Client\Client;
-use Redmine\Tests\Fixtures\MockClient;
+use Redmine\Http\HttpClient;
+use Redmine\Tests\Fixtures\AssertingHttpClient;
 
 /**
  * @author     Malte Gerth <mail@malte-gerth.de>
@@ -15,12 +15,50 @@
 #[CoversClass(IssueStatus::class)]
 class IssueStatusTest extends TestCase
 {
+    public function testExtendingTheClassTriggersDeprecationWarning(): void
+    {
+        // PHPUnit 10 compatible way to test trigger_error().
+        set_error_handler(
+            function ($errno, $errstr): bool {
+                $this->assertSame(
+                    'Class `Redmine\Api\IssueStatus` will declared as final in v3.0.0, stop extending it.',
+                    $errstr,
+                );
+
+                restore_error_handler();
+                return true;
+            },
+            E_USER_DEPRECATED,
+        );
+
+        new class ($this->createStub(HttpClient::class)) extends IssueStatus {};
+    }
+
+    public function testConstructorTriggersDeprecationWarning(): void
+    {
+        // PHPUnit 10 compatible way to test trigger_error().
+        set_error_handler(
+            function ($errno, $errstr): bool {
+                $this->assertSame(
+                    'Method `Redmine\Api\IssueStatus::__construct()` is deprecated since v2.9.0 and will declared as private in v3.0.0, use `Redmine\Api\IssueStatus::fromHttpClient()` instead.',
+                    $errstr,
+                );
+
+                restore_error_handler();
+                return true;
+            },
+            E_USER_DEPRECATED,
+        );
+
+        new IssueStatus($this->createStub(HttpClient::class));
+    }
+
     /**
      * Test all().
      */
     public function testAllTriggersDeprecationWarning(): void
     {
-        $api = new IssueStatus(MockClient::create());
+        $api = IssueStatus::fromHttpClient($this->createStub(HttpClient::class));
 
         // PHPUnit 10 compatible way to test trigger_error().
         set_error_handler(
@@ -47,21 +85,21 @@ function ($errno, $errstr): bool {
     #[DataProvider('getAllData')]
     public function testAllReturnsClientGetResponse(string $response, string $responseType, $expectedResponse): void
     {
-        // Create the used mock objects
-        $client = $this->createMock(Client::class);
-        $client->expects($this->exactly(1))
-            ->method('requestGet')
-            ->with('/issue_statuses.json')
-            ->willReturn(true);
-        $client->expects($this->atLeast(1))
-            ->method('getLastResponseBody')
-            ->willReturn($response);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseContentType')
-            ->willReturn($responseType);
+        $client = AssertingHttpClient::create(
+            $this,
+            [
+                'GET',
+                '/issue_statuses.json',
+                'application/json',
+                '',
+                200,
+                $responseType,
+                $response,
+            ],
+        );
 
         // Create the object under test
-        $api = new IssueStatus($client);
+        $api = IssueStatus::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame($expectedResponse, $api->all());
@@ -86,26 +124,21 @@ public function testAllReturnsClientGetResponseWithParametersAndProject(): void
         $response = '["API Response"]';
         $expectedReturn = ['API Response'];
 
-        // Create the used mock objects
-        $client = $this->createMock(Client::class);
-        $client->expects($this->once())
-            ->method('requestGet')
-            ->with(
-                $this->logicalAnd(
-                    $this->stringStartsWith('/issue_statuses.json'),
-                    $this->stringContains('not-used'),
-                ),
-            )
-            ->willReturn(true);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseBody')
-            ->willReturn($response);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseContentType')
-            ->willReturn('application/json');
+        $client = AssertingHttpClient::create(
+            $this,
+            [
+                'GET',
+                '/issue_statuses.json?limit=25&offset=0&0=not-used',
+                'application/json',
+                '',
+                200,
+                'application/json',
+                $response,
+            ],
+        );
 
         // Create the object under test
-        $api = new IssueStatus($client);
+        $api = IssueStatus::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame($expectedReturn, $api->all($parameters));
@@ -123,23 +156,21 @@ public function testListingReturnsNameIdArray(): void
             'IssueStatus 5' => 5,
         ];
 
-        // Create the used mock objects
-        $client = $this->createMock(Client::class);
-        $client->expects($this->once())
-            ->method('requestGet')
-            ->with(
-                $this->stringStartsWith('/issue_statuses.json'),
-            )
-            ->willReturn(true);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseBody')
-            ->willReturn($response);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseContentType')
-            ->willReturn('application/json');
+        $client = AssertingHttpClient::create(
+            $this,
+            [
+                'GET',
+                '/issue_statuses.json',
+                'application/json',
+                '',
+                200,
+                'application/json',
+                $response,
+            ],
+        );
 
         // Create the object under test
-        $api = new IssueStatus($client);
+        $api = IssueStatus::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame($expectedReturn, $api->listing());
@@ -157,23 +188,21 @@ public function testListingCallsGetOnlyTheFirstTime(): void
             'IssueStatus 5' => 5,
         ];
 
-        // Create the used mock objects
-        $client = $this->createMock(Client::class);
-        $client->expects($this->once())
-            ->method('requestGet')
-            ->with(
-                $this->stringStartsWith('/issue_statuses.json'),
-            )
-            ->willReturn(true);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseBody')
-            ->willReturn($response);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseContentType')
-            ->willReturn('application/json');
+        $client = AssertingHttpClient::create(
+            $this,
+            [
+                'GET',
+                '/issue_statuses.json',
+                'application/json',
+                '',
+                200,
+                'application/json',
+                $response,
+            ],
+        );
 
         // Create the object under test
-        $api = new IssueStatus($client);
+        $api = IssueStatus::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame($expectedReturn, $api->listing());
@@ -192,23 +221,30 @@ public function testListingCallsGetEveryTimeWithForceUpdate(): void
             'IssueStatus 5' => 5,
         ];
 
-        // Create the used mock objects
-        $client = $this->createMock(Client::class);
-        $client->expects($this->exactly(2))
-            ->method('requestGet')
-            ->with(
-                $this->stringStartsWith('/issue_statuses.json'),
-            )
-            ->willReturn(true);
-        $client->expects($this->exactly(2))
-            ->method('getLastResponseBody')
-            ->willReturn($response);
-        $client->expects($this->exactly(2))
-            ->method('getLastResponseContentType')
-            ->willReturn('application/json');
+        $client = AssertingHttpClient::create(
+            $this,
+            [
+                'GET',
+                '/issue_statuses.json',
+                'application/json',
+                '',
+                200,
+                'application/json',
+                $response,
+            ],
+            [
+                'GET',
+                '/issue_statuses.json',
+                'application/json',
+                '',
+                200,
+                'application/json',
+                $response,
+            ],
+        );
 
         // Create the object under test
-        $api = new IssueStatus($client);
+        $api = IssueStatus::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame($expectedReturn, $api->listing(true));
@@ -220,15 +256,22 @@ public function testListingCallsGetEveryTimeWithForceUpdate(): void
      */
     public function testListingTriggersDeprecationWarning(): void
     {
-        $client = $this->createStub(Client::class);
-        $client->method('requestGet')
-            ->willReturn(true);
-        $client->method('getLastResponseBody')
-            ->willReturn('{"issue_statuses":[{"id":1,"name":"IssueStatus 1"},{"id":5,"name":"IssueStatus 5"}]}');
-        $client->method('getLastResponseContentType')
-            ->willReturn('application/json');
+        $response = '{"issue_statuses":[{"id":1,"name":"IssueStatus 1"},{"id":5,"name":"IssueStatus 5"}]}';
+
+        $client = AssertingHttpClient::create(
+            $this,
+            [
+                'GET',
+                '/issue_statuses.json',
+                'application/json',
+                '',
+                200,
+                'application/json',
+                $response,
+            ],
+        );
 
-        $api = new IssueStatus($client);
+        $api = IssueStatus::fromHttpClient($client);
 
         // PHPUnit 10 compatible way to test trigger_error().
         set_error_handler(
@@ -255,23 +298,21 @@ public function testGetIdByNameMakesGetRequest(): void
         // Test values
         $response = '{"issue_statuses":[{"id":5,"name":"IssueStatus 5"}]}';
 
-        // Create the used mock objects
-        $client = $this->createMock(Client::class);
-        $client->expects($this->once())
-            ->method('requestGet')
-            ->with(
-                $this->stringStartsWith('/issue_statuses.json'),
-            )
-            ->willReturn(true);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseBody')
-            ->willReturn($response);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseContentType')
-            ->willReturn('application/json');
+        $client = AssertingHttpClient::create(
+            $this,
+            [
+                'GET',
+                '/issue_statuses.json',
+                'application/json',
+                '',
+                200,
+                'application/json',
+                $response,
+            ],
+        );
 
         // Create the object under test
-        $api = new IssueStatus($client);
+        $api = IssueStatus::fromHttpClient($client);
 
         // Perform the tests
         $this->assertFalse($api->getIdByName('IssueStatus 1'));
@@ -280,15 +321,22 @@ public function testGetIdByNameMakesGetRequest(): void
 
     public function testGetIdByNameTriggersDeprecationWarning(): void
     {
-        $client = $this->createStub(Client::class);
-        $client->method('requestGet')
-            ->willReturn(true);
-        $client->method('getLastResponseBody')
-            ->willReturn('{"issue_statuses":[{"id":1,"name":"IssueStatus 1"},{"id":5,"name":"IssueStatus 5"}]}');
-        $client->method('getLastResponseContentType')
-            ->willReturn('application/json');
-
-        $api = new IssueStatus($client);
+        $response = '{"issue_statuses":[{"id":1,"name":"IssueStatus 1"},{"id":5,"name":"IssueStatus 5"}]}';
+
+        $client = AssertingHttpClient::create(
+            $this,
+            [
+                'GET',
+                '/issue_statuses.json',
+                'application/json',
+                '',
+                200,
+                'application/json',
+                $response,
+            ],
+        );
+
+        $api = IssueStatus::fromHttpClient($client);
 
         // PHPUnit 10 compatible way to test trigger_error().
         set_error_handler(
diff --git a/tests/Unit/Api/IssueTest.php b/tests/Unit/Api/IssueTest.php
index cfddb4bc..3fef1310 100644
--- a/tests/Unit/Api/IssueTest.php
+++ b/tests/Unit/Api/IssueTest.php
@@ -13,9 +13,7 @@
 use Redmine\Api\User;
 use Redmine\Client\Client;
 use Redmine\Http\HttpClient;
-use Redmine\Http\Response;
 use Redmine\Tests\Fixtures\AssertingHttpClient;
-use Redmine\Tests\Fixtures\MockClient;
 
 /**
  * @author     Malte Gerth <mail@malte-gerth.de>
@@ -23,6 +21,44 @@
 #[CoversClass(Issue::class)]
 class IssueTest extends TestCase
 {
+    public function testExtendingTheClassTriggersDeprecationWarning(): void
+    {
+        // PHPUnit 10 compatible way to test trigger_error().
+        set_error_handler(
+            function ($errno, $errstr): bool {
+                $this->assertSame(
+                    'Class `Redmine\Api\Issue` will declared as final in v3.0.0, stop extending it.',
+                    $errstr,
+                );
+
+                restore_error_handler();
+                return true;
+            },
+            E_USER_DEPRECATED,
+        );
+
+        new class ($this->createStub(HttpClient::class)) extends Issue {};
+    }
+
+    public function testConstructorTriggersDeprecationWarning(): void
+    {
+        // PHPUnit 10 compatible way to test trigger_error().
+        set_error_handler(
+            function ($errno, $errstr): bool {
+                $this->assertSame(
+                    'Method `Redmine\Api\Issue::__construct()` is deprecated since v2.9.0 and will declared as private in v3.0.0, use `Redmine\Api\Issue::fromHttpClient()` instead.',
+                    $errstr,
+                );
+
+                restore_error_handler();
+                return true;
+            },
+            E_USER_DEPRECATED,
+        );
+
+        new Issue($this->createStub(HttpClient::class));
+    }
+
     public static function getPriorityConstantsData(): array
     {
         return [
@@ -50,7 +86,7 @@ public function testPriorityConstants(int $expected, int $value): void
      */
     public function testAllTriggersDeprecationWarning(): void
     {
-        $api = new Issue(MockClient::create());
+        $api = Issue::fromHttpClient($this->createStub(HttpClient::class));
 
         // PHPUnit 10 compatible way to test trigger_error().
         set_error_handler(
@@ -77,21 +113,21 @@ function ($errno, $errstr): bool {
     #[DataProvider('getAllData')]
     public function testAllReturnsClientGetResponse(string $response, string $responseType, $expectedResponse): void
     {
-        // Create the used mock objects
-        $client = $this->createMock(Client::class);
-        $client->expects($this->exactly(1))
-            ->method('requestGet')
-            ->with('/issues.json')
-            ->willReturn(true);
-        $client->expects($this->atLeast(1))
-            ->method('getLastResponseBody')
-            ->willReturn($response);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseContentType')
-            ->willReturn($responseType);
+        $client = AssertingHttpClient::create(
+            $this,
+            [
+                'GET',
+                '/issues.json',
+                'application/json',
+                '',
+                200,
+                $responseType,
+                $response,
+            ],
+        );
 
         // Create the object under test
-        $api = new Issue($client);
+        $api = Issue::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame($expectedResponse, $api->all());
@@ -116,26 +152,21 @@ public function testAllReturnsClientGetResponseWithParameters(): void
         $response = '["API Response"]';
         $expectedReturn = ['API Response'];
 
-        // Create the used mock objects
-        $client = $this->createMock(Client::class);
-        $client->expects($this->once())
-            ->method('requestGet')
-            ->with(
-                $this->logicalAnd(
-                    $this->stringStartsWith('/issues.json'),
-                    $this->stringContains('not-used'),
-                ),
-            )
-            ->willReturn(true);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseBody')
-            ->willReturn($response);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseContentType')
-            ->willReturn('application/json');
+        $client = AssertingHttpClient::create(
+            $this,
+            [
+                'GET',
+                '/issues.json?limit=25&offset=0&0=not-used',
+                'application/json',
+                '',
+                200,
+                'application/json',
+                $response,
+            ],
+        );
 
         // Create the object under test
-        $api = new Issue($client);
+        $api = Issue::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame($expectedReturn, $api->all($parameters));
@@ -157,8 +188,7 @@ public function testCreateWithClientCleansParameters(): void
             'author' => 'user_4',
         ];
 
-        // Create the used mock objects
-        $httpClient = AssertingHttpClient::create(
+        $client = AssertingHttpClient::create(
             $this,
             [
                 'GET',
@@ -207,21 +237,21 @@ public function testCreateWithClientCleansParameters(): void
             ],
         );
 
-        $client = $this->createMock(Client::class);
-        $client->expects($this->exactly(5))
+        $legacyClient = $this->createMock(Client::class);
+        $legacyClient->expects($this->exactly(5))
             ->method('getApi')
             ->willReturnMap(
                 [
-                    ['project', new Project($httpClient)],
-                    ['issue_category', new IssueCategory($httpClient)],
-                    ['issue_status', new IssueStatus($httpClient)],
-                    ['tracker', new Tracker($httpClient)],
-                    ['user', new User($httpClient)],
+                    ['project', Project::fromHttpClient($client)],
+                    ['issue_category', IssueCategory::fromHttpClient($client)],
+                    ['issue_status', IssueStatus::fromHttpClient($client)],
+                    ['tracker', new Tracker($client)],
+                    ['user', new User($client)],
                 ],
             )
         ;
 
-        $client->expects($this->once())
+        $legacyClient->expects($this->once())
             ->method('requestPost')
             ->with(
                 '/issues.xml',
@@ -232,15 +262,15 @@ public function testCreateWithClientCleansParameters(): void
                 XML,
             )
             ->willReturn(true);
-        $client->expects($this->exactly(1))
+        $legacyClient->expects($this->exactly(1))
             ->method('getLastResponseBody')
             ->willReturn($response);
-        $client->expects($this->exactly(1))
+        $legacyClient->expects($this->exactly(1))
             ->method('getLastResponseContentType')
             ->willReturn('application/xml');
 
         // Create the object under test
-        $api = new Issue($client);
+        $api = new Issue($legacyClient);
 
         // Perform the tests
         $this->assertXmlStringEqualsXmlString($response, $api->create($parameters)->asXML());
diff --git a/tests/Unit/Api/Membership/CreateTest.php b/tests/Unit/Api/Membership/CreateTest.php
index 2cbfd387..4c88f763 100644
--- a/tests/Unit/Api/Membership/CreateTest.php
+++ b/tests/Unit/Api/Membership/CreateTest.php
@@ -34,7 +34,7 @@ public function testCreateReturnsCorrectResponse(int $identifier, array $paramet
         );
 
         // Create the object under test
-        $api = new Membership($client);
+        $api = Membership::fromHttpClient($client);
 
         // Perform the tests
         $return = $api->create($identifier, $parameters);
@@ -81,7 +81,7 @@ public function testCreateReturnsEmptyString(): void
         );
 
         // Create the object under test
-        $api = new Membership($client);
+        $api = Membership::fromHttpClient($client);
 
         // Perform the tests
         $return = $api->create(5, ['user_id' => 4, 'role_ids' => 2]);
@@ -91,11 +91,10 @@ public function testCreateReturnsEmptyString(): void
 
     public function testCreateThrowsExceptionWithEmptyParameters(): void
     {
-        // Create the used mock objects
         $client = $this->createStub(HttpClient::class);
 
         // Create the object under test
-        $api = new Membership($client);
+        $api = Membership::fromHttpClient($client);
 
         $this->expectException(MissingParameterException::class);
         $this->expectExceptionMessage('Theses parameters are mandatory: `user_id`, `role_ids`');
@@ -110,11 +109,10 @@ public function testCreateThrowsExceptionWithEmptyParameters(): void
     #[DataProvider('incompleteCreateParameterProvider')]
     public function testCreateThrowsExceptionIfMandatoyParametersAreMissing(array $parameters): void
     {
-        // Create the used mock objects
         $client = $this->createStub(HttpClient::class);
 
         // Create the object under test
-        $api = new Membership($client);
+        $api = Membership::fromHttpClient($client);
 
         $this->expectException(MissingParameterException::class);
         $this->expectExceptionMessage('Theses parameters are mandatory: `user_id`, `role_ids`');
diff --git a/tests/Unit/Api/Membership/FromHttpClientTest.php b/tests/Unit/Api/Membership/FromHttpClientTest.php
new file mode 100644
index 00000000..98998f14
--- /dev/null
+++ b/tests/Unit/Api/Membership/FromHttpClientTest.php
@@ -0,0 +1,21 @@
+<?php
+
+namespace Redmine\Tests\Unit\Api\Membership;
+
+use PHPUnit\Framework\Attributes\CoversClass;
+use PHPUnit\Framework\TestCase;
+use Redmine\Api\Membership;
+use Redmine\Http\HttpClient;
+
+#[CoversClass(Membership::class)]
+class FromHttpClientTest extends TestCase
+{
+    public function testReturnsCorrectObject(): void
+    {
+        $httpClient = $this->createStub(HttpClient::class);
+
+        $api = Membership::fromHttpClient($httpClient);
+
+        $this->assertInstanceOf(Membership::class, $api);
+    }
+}
diff --git a/tests/Unit/Api/Membership/ListByProjectTest.php b/tests/Unit/Api/Membership/ListByProjectTest.php
index b1bac7be..95a808c4 100644
--- a/tests/Unit/Api/Membership/ListByProjectTest.php
+++ b/tests/Unit/Api/Membership/ListByProjectTest.php
@@ -6,10 +6,10 @@
 use PHPUnit\Framework\Attributes\DataProviderExternal;
 use PHPUnit\Framework\TestCase;
 use Redmine\Api\Membership;
-use Redmine\Client\Client;
 use Redmine\Exception\InvalidParameterException;
 use Redmine\Exception\UnexpectedResponseException;
-use Redmine\Tests\Fixtures\MockClient;
+use Redmine\Http\HttpClient;
+use Redmine\Tests\Fixtures\AssertingHttpClient;
 use Redmine\Tests\Fixtures\TestDataProvider;
 
 #[CoversClass(Membership::class)]
@@ -21,21 +21,21 @@ public function testListByProjectWithoutParametersReturnsResponse(): void
         $response = '["API Response"]';
         $expectedReturn = ['API Response'];
 
-        // Create the used mock objects
-        $client = $this->createMock(Client::class);
-        $client->expects($this->once())
-            ->method('requestGet')
-            ->with('/projects/5/memberships.json')
-            ->willReturn(true);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseBody')
-            ->willReturn($response);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseContentType')
-            ->willReturn('application/json');
+        $client = AssertingHttpClient::create(
+            $this,
+            [
+                'GET',
+                '/projects/5/memberships.json',
+                'application/json',
+                '',
+                200,
+                'application/json',
+                $response,
+            ],
+        );
 
         // Create the object under test
-        $api = new Membership($client);
+        $api = Membership::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame($expectedReturn, $api->listByProject(5));
@@ -48,21 +48,21 @@ public function testListByProjectWithParametersReturnsResponse(): void
         $response = '["API Response"]';
         $expectedReturn = ['API Response'];
 
-        // Create the used mock objects
-        $client = $this->createMock(Client::class);
-        $client->expects($this->once())
-            ->method('requestGet')
-            ->with('/projects/project-slug/memberships.json?limit=25&offset=0&0=not-used')
-            ->willReturn(true);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseBody')
-            ->willReturn($response);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseContentType')
-            ->willReturn('application/json');
+        $client = AssertingHttpClient::create(
+            $this,
+            [
+                'GET',
+                '/projects/project-slug/memberships.json?limit=25&offset=0&0=not-used',
+                'application/json',
+                '',
+                200,
+                'application/json',
+                $response,
+            ],
+        );
 
         // Create the object under test
-        $api = new Membership($client);
+        $api = Membership::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame($expectedReturn, $api->listByProject('project-slug', $parameters));
@@ -74,7 +74,7 @@ public function testListByProjectWithParametersReturnsResponse(): void
     #[DataProviderExternal(TestDataProvider::class, 'getInvalidProjectIdentifiers')]
     public function testListByProjectWithWrongProjectIdentifierThrowsException($projectIdentifier): void
     {
-        $api = new Membership(MockClient::create());
+        $api = Membership::fromHttpClient($this->createStub(HttpClient::class));
 
         $this->expectException(InvalidParameterException::class);
         $this->expectExceptionMessage('Redmine\Api\Membership::listByProject(): Argument #1 ($projectIdentifier) must be of type int or string');
@@ -84,21 +84,23 @@ public function testListByProjectWithWrongProjectIdentifierThrowsException($proj
 
     public function testListByProjectThrowsException(): void
     {
-        // Create the used mock objects
-        $client = $this->createMock(Client::class);
-        $client->expects($this->exactly(1))
-            ->method('requestGet')
-            ->with('/projects/5/memberships.json')
-            ->willReturn(true);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseBody')
-            ->willReturn('');
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseContentType')
-            ->willReturn('application/json');
+        $response = '';
+
+        $client = AssertingHttpClient::create(
+            $this,
+            [
+                'GET',
+                '/projects/5/memberships.json',
+                'application/json',
+                '',
+                200,
+                'application/json',
+                $response,
+            ],
+        );
 
         // Create the object under test
-        $api = new Membership($client);
+        $api = Membership::fromHttpClient($client);
 
         $this->expectException(UnexpectedResponseException::class);
         $this->expectExceptionMessage('The Redmine server replied with an unexpected response.');
diff --git a/tests/Unit/Api/Membership/RemoveMemberTest.php b/tests/Unit/Api/Membership/RemoveMemberTest.php
index 495ea5d3..8c2fd51a 100644
--- a/tests/Unit/Api/Membership/RemoveMemberTest.php
+++ b/tests/Unit/Api/Membership/RemoveMemberTest.php
@@ -40,7 +40,7 @@ public function testRemoveMemberReturnsCorrectResponse(int $projectIdentifier, i
         );
 
         // Create the object under test
-        $api = new Membership($client);
+        $api = Membership::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame($response, $api->removeMember($projectIdentifier, $userId, $params));
@@ -84,7 +84,7 @@ public function testRemoveMemberReturnsFalseIfUserIsNotMemberOfProject(): void
         );
 
         // Create the object under test
-        $api = new Membership($client);
+        $api = Membership::fromHttpClient($client);
 
         // Perform the tests
         $this->assertFalse($api->removeMember(1, 2));
@@ -106,7 +106,7 @@ public function testRemoveMemberReturnsFalseIfMemberlistIsMissing(): void
         );
 
         // Create the object under test
-        $api = new Membership($client);
+        $api = Membership::fromHttpClient($client);
 
         // Perform the tests
         $this->assertFalse($api->removeMember(1, 2));
diff --git a/tests/Unit/Api/Membership/RemoveTest.php b/tests/Unit/Api/Membership/RemoveTest.php
index b18f65b0..4e668632 100644
--- a/tests/Unit/Api/Membership/RemoveTest.php
+++ b/tests/Unit/Api/Membership/RemoveTest.php
@@ -31,7 +31,7 @@ public function testRemoveReturnsCorrectResponse(int $id, string $expectedPath,
         );
 
         // Create the object under test
-        $api = new Membership($client);
+        $api = Membership::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame($response, $api->remove($id));
diff --git a/tests/Unit/Api/Membership/UpdateTest.php b/tests/Unit/Api/Membership/UpdateTest.php
index f6b70d20..df0a80bf 100644
--- a/tests/Unit/Api/Membership/UpdateTest.php
+++ b/tests/Unit/Api/Membership/UpdateTest.php
@@ -33,7 +33,7 @@ public function testUpdateReturnsCorrectResponse(int $id, array $parameters, str
         );
 
         // Create the object under test
-        $api = new Membership($client);
+        $api = Membership::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame('', $api->update($id, $parameters));
@@ -78,7 +78,7 @@ public function testUpdateReturnsEmptyString(): void
         );
 
         // Create the object under test
-        $api = new Membership($client);
+        $api = Membership::fromHttpClient($client);
 
         // Perform the tests
         $return = $api->update(5, ['user_id' => 4, 'role_ids' => 2]);
@@ -92,7 +92,7 @@ public function testUpdateThrowsExceptionWithEmptyParameters(): void
         $client = $this->createStub(HttpClient::class);
 
         // Create the object under test
-        $api = new Membership($client);
+        $api = Membership::fromHttpClient($client);
 
         $this->expectException(MissingParameterException::class);
         $this->expectExceptionMessage('Theses parameters are mandatory: `role_ids`');
@@ -111,7 +111,7 @@ public function testUpdateThrowsExceptionIfMandatoyParametersAreMissing(array $p
         $client = $this->createStub(HttpClient::class);
 
         // Create the object under test
-        $api = new Membership($client);
+        $api = Membership::fromHttpClient($client);
 
         $this->expectException(MissingParameterException::class);
         $this->expectExceptionMessage('Theses parameters are mandatory: `role_ids`');
diff --git a/tests/Unit/Api/MembershipTest.php b/tests/Unit/Api/MembershipTest.php
index 70af3a16..3bb0c5ce 100644
--- a/tests/Unit/Api/MembershipTest.php
+++ b/tests/Unit/Api/MembershipTest.php
@@ -6,8 +6,8 @@
 use PHPUnit\Framework\Attributes\DataProvider;
 use PHPUnit\Framework\TestCase;
 use Redmine\Api\Membership;
-use Redmine\Client\Client;
-use Redmine\Tests\Fixtures\MockClient;
+use Redmine\Http\HttpClient;
+use Redmine\Tests\Fixtures\AssertingHttpClient;
 
 /**
  * @author     Malte Gerth <mail@malte-gerth.de>
@@ -15,12 +15,50 @@
 #[CoversClass(Membership::class)]
 class MembershipTest extends TestCase
 {
+    public function testExtendingTheClassTriggersDeprecationWarning(): void
+    {
+        // PHPUnit 10 compatible way to test trigger_error().
+        set_error_handler(
+            function ($errno, $errstr): bool {
+                $this->assertSame(
+                    'Class `Redmine\Api\Membership` will declared as final in v3.0.0, stop extending it.',
+                    $errstr,
+                );
+
+                restore_error_handler();
+                return true;
+            },
+            E_USER_DEPRECATED,
+        );
+
+        new class ($this->createStub(HttpClient::class)) extends Membership {};
+    }
+
+    public function testConstructorTriggersDeprecationWarning(): void
+    {
+        // PHPUnit 10 compatible way to test trigger_error().
+        set_error_handler(
+            function ($errno, $errstr): bool {
+                $this->assertSame(
+                    'Method `Redmine\Api\Membership::__construct()` is deprecated since v2.9.0 and will declared as private in v3.0.0, use `Redmine\Api\Membership::fromHttpClient()` instead.',
+                    $errstr,
+                );
+
+                restore_error_handler();
+                return true;
+            },
+            E_USER_DEPRECATED,
+        );
+
+        new Membership($this->createStub(HttpClient::class));
+    }
+
     /**
      * Test all().
      */
     public function testAllTriggersDeprecationWarning(): void
     {
-        $api = new Membership(MockClient::create());
+        $api = Membership::fromHttpClient($this->createStub(HttpClient::class));
 
         // PHPUnit 10 compatible way to test trigger_error().
         set_error_handler(
@@ -47,21 +85,21 @@ function ($errno, $errstr): bool {
     #[DataProvider('getAllData')]
     public function testAllReturnsClientGetResponseWithProject(string $response, string $responseType, $expectedResponse): void
     {
-        // Create the used mock objects
-        $client = $this->createMock(Client::class);
-        $client->expects($this->exactly(1))
-            ->method('requestGet')
-            ->with('/projects/5/memberships.json')
-            ->willReturn(true);
-        $client->expects($this->atLeast(1))
-            ->method('getLastResponseBody')
-            ->willReturn($response);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseContentType')
-            ->willReturn($responseType);
+        $client = AssertingHttpClient::create(
+            $this,
+            [
+                'GET',
+                '/projects/5/memberships.json',
+                'application/json',
+                '',
+                200,
+                $responseType,
+                $response,
+            ],
+        );
 
         // Create the object under test
-        $api = new Membership($client);
+        $api = Membership::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame($expectedResponse, $api->all(5));
@@ -86,26 +124,21 @@ public function testAllReturnsClientGetResponseWithParametersAndProject(): void
         $response = '["API Response"]';
         $expectedReturn = ['API Response'];
 
-        // Create the used mock objects
-        $client = $this->createMock(Client::class);
-        $client->expects($this->once())
-            ->method('requestGet')
-            ->with(
-                $this->logicalAnd(
-                    $this->stringStartsWith('/projects/5/memberships.json'),
-                    $this->stringContains('not-used'),
-                ),
-            )
-            ->willReturn(true);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseBody')
-            ->willReturn($response);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseContentType')
-            ->willReturn('application/json');
+        $client = AssertingHttpClient::create(
+            $this,
+            [
+                'GET',
+                '/projects/5/memberships.json?limit=25&offset=0&0=not-used',
+                'application/json',
+                '',
+                200,
+                'application/json',
+                $response,
+            ],
+        );
 
         // Create the object under test
-        $api = new Membership($client);
+        $api = Membership::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame($expectedReturn, $api->all(5, $parameters));
diff --git a/tests/Unit/Api/News/FromHttpClientTest.php b/tests/Unit/Api/News/FromHttpClientTest.php
new file mode 100644
index 00000000..7785d5d3
--- /dev/null
+++ b/tests/Unit/Api/News/FromHttpClientTest.php
@@ -0,0 +1,21 @@
+<?php
+
+namespace Redmine\Tests\Unit\Api\News;
+
+use PHPUnit\Framework\Attributes\CoversClass;
+use PHPUnit\Framework\TestCase;
+use Redmine\Api\News;
+use Redmine\Http\HttpClient;
+
+#[CoversClass(News::class)]
+class FromHttpClientTest extends TestCase
+{
+    public function testReturnsCorrectObject(): void
+    {
+        $httpClient = $this->createStub(HttpClient::class);
+
+        $api = News::fromHttpClient($httpClient);
+
+        $this->assertInstanceOf(News::class, $api);
+    }
+}
diff --git a/tests/Unit/Api/News/ListByProjectTest.php b/tests/Unit/Api/News/ListByProjectTest.php
index 4a234d4c..ab9c4a72 100644
--- a/tests/Unit/Api/News/ListByProjectTest.php
+++ b/tests/Unit/Api/News/ListByProjectTest.php
@@ -6,10 +6,10 @@
 use PHPUnit\Framework\Attributes\DataProviderExternal;
 use PHPUnit\Framework\TestCase;
 use Redmine\Api\News;
-use Redmine\Client\Client;
 use Redmine\Exception\InvalidParameterException;
 use Redmine\Exception\UnexpectedResponseException;
-use Redmine\Tests\Fixtures\MockClient;
+use Redmine\Http\HttpClient;
+use Redmine\Tests\Fixtures\AssertingHttpClient;
 use Redmine\Tests\Fixtures\TestDataProvider;
 
 #[CoversClass(News::class)]
@@ -22,21 +22,21 @@ public function testListByProjectWithoutParametersReturnsResponse(): void
         $response = '["API Response"]';
         $expectedReturn = ['API Response'];
 
-        // Create the used mock objects
-        $client = $this->createMock(Client::class);
-        $client->expects($this->once())
-            ->method('requestGet')
-            ->with('/projects/5/news.json')
-            ->willReturn(true);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseBody')
-            ->willReturn($response);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseContentType')
-            ->willReturn('application/json');
+        $client = AssertingHttpClient::create(
+            $this,
+            [
+                'GET',
+                '/projects/5/news.json',
+                'application/json',
+                '',
+                200,
+                'application/json',
+                $response,
+            ],
+        );
 
         // Create the object under test
-        $api = new News($client);
+        $api = News::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame($expectedReturn, $api->listByProject($projectId));
@@ -50,21 +50,21 @@ public function testListByProjectWithParametersReturnsResponse(): void
         $response = '["API Response"]';
         $expectedReturn = ['API Response'];
 
-        // Create the used mock objects
-        $client = $this->createMock(Client::class);
-        $client->expects($this->once())
-            ->method('requestGet')
-            ->with('/projects/5/news.json?limit=25&offset=0&0=not-used')
-            ->willReturn(true);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseBody')
-            ->willReturn($response);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseContentType')
-            ->willReturn('application/json');
+        $client = AssertingHttpClient::create(
+            $this,
+            [
+                'GET',
+                '/projects/5/news.json?limit=25&offset=0&0=not-used',
+                'application/json',
+                '',
+                200,
+                'application/json',
+                $response,
+            ],
+        );
 
         // Create the object under test
-        $api = new News($client);
+        $api = News::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame($expectedReturn, $api->listByProject($projectId, $parameters));
@@ -76,7 +76,7 @@ public function testListByProjectWithParametersReturnsResponse(): void
     #[DataProviderExternal(TestDataProvider::class, 'getInvalidProjectIdentifiers')]
     public function testListByProjectWithWrongProjectIdentifierThrowsException($projectIdentifier): void
     {
-        $api = new News(MockClient::create());
+        $api = News::fromHttpClient($this->createStub(HttpClient::class));
 
         $this->expectException(InvalidParameterException::class);
         $this->expectExceptionMessage('Redmine\Api\News::listByProject(): Argument #1 ($projectIdentifier) must be of type int or string');
@@ -86,21 +86,23 @@ public function testListByProjectWithWrongProjectIdentifierThrowsException($proj
 
     public function testListByProjectThrowsException(): void
     {
-        // Create the used mock objects
-        $client = $this->createMock(Client::class);
-        $client->expects($this->exactly(1))
-            ->method('requestGet')
-            ->with('/projects/5/news.json')
-            ->willReturn(true);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseBody')
-            ->willReturn('');
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseContentType')
-            ->willReturn('application/json');
+        $response = '';
+
+        $client = AssertingHttpClient::create(
+            $this,
+            [
+                'GET',
+                '/projects/5/news.json',
+                'application/json',
+                '',
+                200,
+                'application/json',
+                $response,
+            ],
+        );
 
         // Create the object under test
-        $api = new News($client);
+        $api = News::fromHttpClient($client);
 
         $this->expectException(UnexpectedResponseException::class);
         $this->expectExceptionMessage('The Redmine server replied with an unexpected response.');
diff --git a/tests/Unit/Api/News/ListTest.php b/tests/Unit/Api/News/ListTest.php
index d8116065..0732cd2a 100644
--- a/tests/Unit/Api/News/ListTest.php
+++ b/tests/Unit/Api/News/ListTest.php
@@ -5,8 +5,8 @@
 use PHPUnit\Framework\Attributes\CoversClass;
 use PHPUnit\Framework\TestCase;
 use Redmine\Api\News;
-use Redmine\Client\Client;
 use Redmine\Exception\UnexpectedResponseException;
+use Redmine\Tests\Fixtures\AssertingHttpClient;
 
 #[CoversClass(News::class)]
 class ListTest extends TestCase
@@ -17,21 +17,21 @@ public function testListWithoutParametersReturnsResponse(): void
         $response = '["API Response"]';
         $expectedReturn = ['API Response'];
 
-        // Create the used mock objects
-        $client = $this->createMock(Client::class);
-        $client->expects($this->once())
-            ->method('requestGet')
-            ->with('/news.json')
-            ->willReturn(true);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseBody')
-            ->willReturn($response);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseContentType')
-            ->willReturn('application/json');
+        $client = AssertingHttpClient::create(
+            $this,
+            [
+                'GET',
+                '/news.json',
+                'application/json',
+                '',
+                200,
+                'application/json',
+                $response,
+            ],
+        );
 
         // Create the object under test
-        $api = new News($client);
+        $api = News::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame($expectedReturn, $api->list());
@@ -44,21 +44,21 @@ public function testListWithParametersReturnsResponse(): void
         $response = '["API Response"]';
         $expectedReturn = ['API Response'];
 
-        // Create the used mock objects
-        $client = $this->createMock(Client::class);
-        $client->expects($this->once())
-            ->method('requestGet')
-            ->with('/news.json?limit=25&offset=0&0=not-used')
-            ->willReturn(true);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseBody')
-            ->willReturn($response);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseContentType')
-            ->willReturn('application/json');
+        $client = AssertingHttpClient::create(
+            $this,
+            [
+                'GET',
+                '/news.json?limit=25&offset=0&0=not-used',
+                'application/json',
+                '',
+                200,
+                'application/json',
+                $response,
+            ],
+        );
 
         // Create the object under test
-        $api = new News($client);
+        $api = News::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame($expectedReturn, $api->list($parameters));
@@ -66,21 +66,23 @@ public function testListWithParametersReturnsResponse(): void
 
     public function testListThrowsException(): void
     {
-        // Create the used mock objects
-        $client = $this->createMock(Client::class);
-        $client->expects($this->exactly(1))
-            ->method('requestGet')
-            ->with('/news.json')
-            ->willReturn(true);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseBody')
-            ->willReturn('');
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseContentType')
-            ->willReturn('application/json');
+        $response = '';
+
+        $client = AssertingHttpClient::create(
+            $this,
+            [
+                'GET',
+                '/news.json',
+                'application/json',
+                '',
+                200,
+                'application/json',
+                $response,
+            ],
+        );
 
         // Create the object under test
-        $api = new News($client);
+        $api = News::fromHttpClient($client);
 
         $this->expectException(UnexpectedResponseException::class);
         $this->expectExceptionMessage('The Redmine server replied with an unexpected response.');
diff --git a/tests/Unit/Api/NewsTest.php b/tests/Unit/Api/NewsTest.php
index 32b589f4..5daed4ee 100644
--- a/tests/Unit/Api/NewsTest.php
+++ b/tests/Unit/Api/NewsTest.php
@@ -6,8 +6,8 @@
 use PHPUnit\Framework\Attributes\DataProvider;
 use PHPUnit\Framework\TestCase;
 use Redmine\Api\News;
-use Redmine\Client\Client;
-use Redmine\Tests\Fixtures\MockClient;
+use Redmine\Http\HttpClient;
+use Redmine\Tests\Fixtures\AssertingHttpClient;
 
 /**
  * @author     Malte Gerth <mail@malte-gerth.de>
@@ -15,12 +15,50 @@
 #[CoversClass(News::class)]
 class NewsTest extends TestCase
 {
+    public function testExtendingTheClassTriggersDeprecationWarning(): void
+    {
+        // PHPUnit 10 compatible way to test trigger_error().
+        set_error_handler(
+            function ($errno, $errstr): bool {
+                $this->assertSame(
+                    'Class `Redmine\Api\News` will declared as final in v3.0.0, stop extending it.',
+                    $errstr,
+                );
+
+                restore_error_handler();
+                return true;
+            },
+            E_USER_DEPRECATED,
+        );
+
+        new class ($this->createStub(HttpClient::class)) extends News {};
+    }
+
+    public function testConstructorTriggersDeprecationWarning(): void
+    {
+        // PHPUnit 10 compatible way to test trigger_error().
+        set_error_handler(
+            function ($errno, $errstr): bool {
+                $this->assertSame(
+                    'Method `Redmine\Api\News::__construct()` is deprecated since v2.9.0 and will declared as private in v3.0.0, use `Redmine\Api\News::fromHttpClient()` instead.',
+                    $errstr,
+                );
+
+                restore_error_handler();
+                return true;
+            },
+            E_USER_DEPRECATED,
+        );
+
+        new News($this->createStub(HttpClient::class));
+    }
+
     /**
      * Test all().
      */
     public function testAllTriggersDeprecationWarning(): void
     {
-        $api = new News(MockClient::create());
+        $api = News::fromHttpClient($this->createStub(HttpClient::class));
 
         // PHPUnit 10 compatible way to test trigger_error().
         set_error_handler(
@@ -47,21 +85,21 @@ function ($errno, $errstr): bool {
     #[DataProvider('getAllData')]
     public function testAllReturnsClientGetResponse(string $response, string $responseType, $expectedResponse): void
     {
-        // Create the used mock objects
-        $client = $this->createMock(Client::class);
-        $client->expects($this->exactly(1))
-            ->method('requestGet')
-            ->with('/news.json')
-            ->willReturn(true);
-        $client->expects($this->atLeast(1))
-            ->method('getLastResponseBody')
-            ->willReturn($response);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseContentType')
-            ->willReturn($responseType);
+        $client = AssertingHttpClient::create(
+            $this,
+            [
+                'GET',
+                '/news.json',
+                'application/json',
+                '',
+                200,
+                $responseType,
+                $response,
+            ],
+        );
 
         // Create the object under test
-        $api = new News($client);
+        $api = News::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame($expectedResponse, $api->all());
@@ -86,23 +124,21 @@ public function testAllReturnsClientGetResponseWithProject(): void
         $response = '["API Response"]';
         $expectedReturn = ['API Response'];
 
-        // Create the used mock objects
-        $client = $this->createMock(Client::class);
-        $client->expects($this->once())
-            ->method('requestGet')
-            ->with(
-                $this->stringStartsWith('/projects/5/news.json'),
-            )
-            ->willReturn(true);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseBody')
-            ->willReturn($response);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseContentType')
-            ->willReturn('application/json');
+        $client = AssertingHttpClient::create(
+            $this,
+            [
+                'GET',
+                '/projects/5/news.json',
+                'application/json',
+                '',
+                200,
+                'application/json',
+                $response,
+            ],
+        );
 
         // Create the object under test
-        $api = new News($client);
+        $api = News::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame($expectedReturn, $api->all($projectId));
@@ -119,23 +155,21 @@ public function testAllReturnsClientGetResponseWithParametersAndProject(): void
         $response = '["API Response"]';
         $expectedReturn = ['API Response'];
 
-        // Create the used mock objects
-        $client = $this->createMock(Client::class);
-        $client->expects($this->once())
-            ->method('requestGet')
-            ->with(
-                $this->stringContains('not-used'),
-            )
-            ->willReturn(true);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseBody')
-            ->willReturn($response);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseContentType')
-            ->willReturn('application/json');
+        $client = AssertingHttpClient::create(
+            $this,
+            [
+                'GET',
+                '/projects/5/news.json?limit=25&offset=0&0=not-used',
+                'application/json',
+                '',
+                200,
+                'application/json',
+                $response,
+            ],
+        );
 
         // Create the object under test
-        $api = new News($client);
+        $api = News::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame($expectedReturn, $api->all($projectId, $parameters));
diff --git a/tests/Unit/Api/Project/ArchiveTest.php b/tests/Unit/Api/Project/ArchiveTest.php
index 6a9216da..8ca6374e 100644
--- a/tests/Unit/Api/Project/ArchiveTest.php
+++ b/tests/Unit/Api/Project/ArchiveTest.php
@@ -28,7 +28,7 @@ public function testArchiveReturnsTrue(): void
             ],
         );
 
-        $api = new Project($client);
+        $api = Project::fromHttpClient($client);
 
         $this->assertTrue($api->archive(5));
     }
@@ -46,7 +46,7 @@ public function testArchiveThrowsUnexpectedResponseException(): void
             ],
         );
 
-        $api = new Project($client);
+        $api = Project::fromHttpClient($client);
 
         $this->expectException(UnexpectedResponseException::class);
         $this->expectExceptionMessage('The Redmine server replied with an unexpected response.');
@@ -58,7 +58,7 @@ public function testArchiveWithoutIntOrStringThrowsInvalidArgumentException(): v
     {
         $client = $this->createStub(HttpClient::class);
 
-        $api = new Project($client);
+        $api = Project::fromHttpClient($client);
 
         $this->expectException(InvalidArgumentException::class);
         $this->expectExceptionMessage('Redmine\Api\Project::archive(): Argument #1 ($projectIdentifier) must be of type int or string');
diff --git a/tests/Unit/Api/Project/CloseTest.php b/tests/Unit/Api/Project/CloseTest.php
index 470f517f..f36901ae 100644
--- a/tests/Unit/Api/Project/CloseTest.php
+++ b/tests/Unit/Api/Project/CloseTest.php
@@ -26,7 +26,7 @@ public function testCloseReturnsTrue(): void
             ],
         );
 
-        $api = new Project($client);
+        $api = Project::fromHttpClient($client);
 
         $this->assertTrue($api->close(5));
     }
@@ -44,7 +44,7 @@ public function testCloseThrowsUnexpectedResponseException(): void
             ],
         );
 
-        $api = new Project($client);
+        $api = Project::fromHttpClient($client);
 
         $this->expectException(UnexpectedResponseException::class);
         $this->expectExceptionMessage('The Redmine server replied with an unexpected response.');
@@ -56,7 +56,7 @@ public function testCloseWithoutIntOrStringThrowsInvalidArgumentException(): voi
     {
         $client = $this->createStub(HttpClient::class);
 
-        $api = new Project($client);
+        $api = Project::fromHttpClient($client);
 
         $this->expectException(InvalidArgumentException::class);
         $this->expectExceptionMessage('Redmine\Api\Project::close(): Argument #1 ($projectIdentifier) must be of type int or string');
diff --git a/tests/Unit/Api/Project/CreateTest.php b/tests/Unit/Api/Project/CreateTest.php
index 87217ceb..13665670 100644
--- a/tests/Unit/Api/Project/CreateTest.php
+++ b/tests/Unit/Api/Project/CreateTest.php
@@ -34,7 +34,7 @@ public function testCreateReturnsCorrectResponse(array $parameters, string $expe
         );
 
         // Create the object under test
-        $api = new Project($client);
+        $api = Project::fromHttpClient($client);
 
         // Perform the tests
         $return = $api->create($parameters);
@@ -147,7 +147,7 @@ public function testCreateReturnsEmptyString(): void
         );
 
         // Create the object under test
-        $api = new Project($client);
+        $api = Project::fromHttpClient($client);
 
         // Perform the tests
         $return = $api->create(['identifier' => 'test-project', 'name' => 'Test Project']);
@@ -161,7 +161,7 @@ public function testCreateThrowsExceptionWithEmptyParameters(): void
         $client = $this->createStub(HttpClient::class);
 
         // Create the object under test
-        $api = new Project($client);
+        $api = Project::fromHttpClient($client);
 
         $this->expectException(MissingParameterException::class);
         $this->expectExceptionMessage('Theses parameters are mandatory: `name`, `identifier`');
@@ -180,7 +180,7 @@ public function testCreateThrowsExceptionIfMandatoyParametersAreMissing(array $p
         $client = $this->createStub(HttpClient::class);
 
         // Create the object under test
-        $api = new Project($client);
+        $api = Project::fromHttpClient($client);
 
         $this->expectException(MissingParameterException::class);
         $this->expectExceptionMessage('Theses parameters are mandatory: `name`, `identifier`');
diff --git a/tests/Unit/Api/Project/FromHttpClientTest.php b/tests/Unit/Api/Project/FromHttpClientTest.php
new file mode 100644
index 00000000..ecb25135
--- /dev/null
+++ b/tests/Unit/Api/Project/FromHttpClientTest.php
@@ -0,0 +1,21 @@
+<?php
+
+namespace Redmine\Tests\Unit\Api\Project;
+
+use PHPUnit\Framework\Attributes\CoversClass;
+use PHPUnit\Framework\TestCase;
+use Redmine\Api\Project;
+use Redmine\Http\HttpClient;
+
+#[CoversClass(Project::class)]
+class FromHttpClientTest extends TestCase
+{
+    public function testReturnsCorrectObject(): void
+    {
+        $httpClient = $this->createStub(HttpClient::class);
+
+        $api = Project::fromHttpClient($httpClient);
+
+        $this->assertInstanceOf(Project::class, $api);
+    }
+}
diff --git a/tests/Unit/Api/Project/ListNamesTest.php b/tests/Unit/Api/Project/ListNamesTest.php
index 44136945..8f2553e1 100644
--- a/tests/Unit/Api/Project/ListNamesTest.php
+++ b/tests/Unit/Api/Project/ListNamesTest.php
@@ -33,7 +33,7 @@ public function testListNamesReturnsCorrectResponse(string $expectedPath, int $r
         );
 
         // Create the object under test
-        $api = new Project($client);
+        $api = Project::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame($expectedResponse, $api->listNames());
@@ -126,7 +126,7 @@ public function testListNamesWithALotOfProjectsHandlesPagination(): void
         );
 
         // Create the object under test
-        $api = new Project($client);
+        $api = Project::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame($assertData, $api->listNames());
@@ -157,7 +157,7 @@ public function testListNamesCallsHttpClientOnlyOnce(): void
         );
 
         // Create the object under test
-        $api = new Project($client);
+        $api = Project::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame([1 => 'Project 1'], $api->listNames());
diff --git a/tests/Unit/Api/Project/ListTest.php b/tests/Unit/Api/Project/ListTest.php
index ff6c7b52..2d7640aa 100644
--- a/tests/Unit/Api/Project/ListTest.php
+++ b/tests/Unit/Api/Project/ListTest.php
@@ -5,8 +5,8 @@
 use PHPUnit\Framework\Attributes\CoversClass;
 use PHPUnit\Framework\TestCase;
 use Redmine\Api\Project;
-use Redmine\Client\Client;
 use Redmine\Exception\UnexpectedResponseException;
+use Redmine\Tests\Fixtures\AssertingHttpClient;
 
 #[CoversClass(Project::class)]
 class ListTest extends TestCase
@@ -17,21 +17,21 @@ public function testListWithoutParametersReturnsResponse(): void
         $response = '["API Response"]';
         $expectedReturn = ['API Response'];
 
-        // Create the used mock objects
-        $client = $this->createMock(Client::class);
-        $client->expects($this->once())
-            ->method('requestGet')
-            ->with('/projects.json')
-            ->willReturn(true);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseBody')
-            ->willReturn($response);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseContentType')
-            ->willReturn('application/json');
+        $client = AssertingHttpClient::create(
+            $this,
+            [
+                'GET',
+                '/projects.json',
+                'application/json',
+                '',
+                200,
+                'application/json',
+                $response,
+            ],
+        );
 
         // Create the object under test
-        $api = new Project($client);
+        $api = Project::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame($expectedReturn, $api->list());
@@ -44,21 +44,21 @@ public function testListWithParametersReturnsResponse(): void
         $response = '["API Response"]';
         $expectedReturn = ['API Response'];
 
-        // Create the used mock objects
-        $client = $this->createMock(Client::class);
-        $client->expects($this->once())
-            ->method('requestGet')
-            ->with('/projects.json?limit=25&offset=0&0=not-used')
-            ->willReturn(true);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseBody')
-            ->willReturn($response);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseContentType')
-            ->willReturn('application/json');
+        $client = AssertingHttpClient::create(
+            $this,
+            [
+                'GET',
+                '/projects.json?limit=25&offset=0&0=not-used',
+                'application/json',
+                '',
+                200,
+                'application/json',
+                $response,
+            ],
+        );
 
         // Create the object under test
-        $api = new Project($client);
+        $api = Project::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame($expectedReturn, $api->list($parameters));
@@ -66,21 +66,23 @@ public function testListWithParametersReturnsResponse(): void
 
     public function testListThrowsException(): void
     {
-        // Create the used mock objects
-        $client = $this->createMock(Client::class);
-        $client->expects($this->exactly(1))
-            ->method('requestGet')
-            ->with('/projects.json')
-            ->willReturn(true);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseBody')
-            ->willReturn('');
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseContentType')
-            ->willReturn('application/json');
+        $response = '';
+
+        $client = AssertingHttpClient::create(
+            $this,
+            [
+                'GET',
+                '/projects.json',
+                'application/json',
+                '',
+                200,
+                'application/json',
+                $response,
+            ],
+        );
 
         // Create the object under test
-        $api = new Project($client);
+        $api = Project::fromHttpClient($client);
 
         $this->expectException(UnexpectedResponseException::class);
         $this->expectExceptionMessage('The Redmine server replied with an unexpected response.');
diff --git a/tests/Unit/Api/Project/RemoveTest.php b/tests/Unit/Api/Project/RemoveTest.php
index 0a1c38c5..1ff74cfd 100644
--- a/tests/Unit/Api/Project/RemoveTest.php
+++ b/tests/Unit/Api/Project/RemoveTest.php
@@ -31,7 +31,7 @@ public function testRemoveReturnsCorrectResponse(int $id, string $expectedPath,
         );
 
         // Create the object under test
-        $api = new Project($client);
+        $api = Project::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame($response, $api->remove($id));
diff --git a/tests/Unit/Api/Project/ReopenTest.php b/tests/Unit/Api/Project/ReopenTest.php
index bb111378..4b4f3f99 100644
--- a/tests/Unit/Api/Project/ReopenTest.php
+++ b/tests/Unit/Api/Project/ReopenTest.php
@@ -26,7 +26,7 @@ public function testReopenReturnsTrue(): void
             ],
         );
 
-        $api = new Project($client);
+        $api = Project::fromHttpClient($client);
 
         $this->assertTrue($api->reopen(5));
     }
@@ -44,7 +44,7 @@ public function testReopenThrowsUnexpectedResponseException(): void
             ],
         );
 
-        $api = new Project($client);
+        $api = Project::fromHttpClient($client);
 
         $this->expectException(UnexpectedResponseException::class);
         $this->expectExceptionMessage('The Redmine server replied with an unexpected response.');
@@ -56,7 +56,7 @@ public function testReopenWithoutIntOrStringThrowsInvalidArgumentException(): vo
     {
         $client = $this->createStub(HttpClient::class);
 
-        $api = new Project($client);
+        $api = Project::fromHttpClient($client);
 
         $this->expectException(InvalidArgumentException::class);
         $this->expectExceptionMessage('Redmine\Api\Project::reopen(): Argument #1 ($projectIdentifier) must be of type int or string');
diff --git a/tests/Unit/Api/Project/ShowTest.php b/tests/Unit/Api/Project/ShowTest.php
index 5d36fd1a..3c30edb6 100644
--- a/tests/Unit/Api/Project/ShowTest.php
+++ b/tests/Unit/Api/Project/ShowTest.php
@@ -31,7 +31,7 @@ public function testShowReturnsCorrectResponse($identifier, array $params, strin
         );
 
         // Create the object under test
-        $api = new Project($client);
+        $api = Project::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame($expectedReturn, $api->show($identifier, $params));
diff --git a/tests/Unit/Api/Project/UnarchiveTest.php b/tests/Unit/Api/Project/UnarchiveTest.php
index e3c57b00..86f777b5 100644
--- a/tests/Unit/Api/Project/UnarchiveTest.php
+++ b/tests/Unit/Api/Project/UnarchiveTest.php
@@ -26,7 +26,7 @@ public function testUnarchiveReturnsTrue(): void
             ],
         );
 
-        $api = new Project($client);
+        $api = Project::fromHttpClient($client);
 
         $this->assertTrue($api->unarchive(5));
     }
@@ -44,7 +44,7 @@ public function testUnarchiveThrowsUnexpectedResponseException(): void
             ],
         );
 
-        $api = new Project($client);
+        $api = Project::fromHttpClient($client);
 
         $this->expectException(UnexpectedResponseException::class);
         $this->expectExceptionMessage('The Redmine server replied with an unexpected response.');
@@ -56,7 +56,7 @@ public function testUnarchiveWithoutIntOrStringThrowsInvalidArgumentException():
     {
         $client = $this->createStub(HttpClient::class);
 
-        $api = new Project($client);
+        $api = Project::fromHttpClient($client);
 
         $this->expectException(InvalidArgumentException::class);
         $this->expectExceptionMessage('Redmine\Api\Project::unarchive(): Argument #1 ($projectIdentifier) must be of type int or string');
diff --git a/tests/Unit/Api/Project/UpdateTest.php b/tests/Unit/Api/Project/UpdateTest.php
index 5f12e417..52fcc23a 100644
--- a/tests/Unit/Api/Project/UpdateTest.php
+++ b/tests/Unit/Api/Project/UpdateTest.php
@@ -33,7 +33,7 @@ public function testUpdateReturnsCorrectResponse(int $id, array $parameters, str
         );
 
         // Create the object under test
-        $api = new Project($client);
+        $api = Project::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame('', $api->update($id, $parameters));
diff --git a/tests/Unit/Api/ProjectTest.php b/tests/Unit/Api/ProjectTest.php
index b88452ca..ec153439 100644
--- a/tests/Unit/Api/ProjectTest.php
+++ b/tests/Unit/Api/ProjectTest.php
@@ -6,8 +6,8 @@
 use PHPUnit\Framework\Attributes\DataProvider;
 use PHPUnit\Framework\TestCase;
 use Redmine\Api\Project;
-use Redmine\Client\Client;
-use Redmine\Tests\Fixtures\MockClient;
+use Redmine\Http\HttpClient;
+use Redmine\Tests\Fixtures\AssertingHttpClient;
 use ReflectionMethod;
 use SimpleXMLElement;
 
@@ -17,12 +17,50 @@
 #[CoversClass(Project::class)]
 class ProjectTest extends TestCase
 {
+    public function testExtendingTheClassTriggersDeprecationWarning(): void
+    {
+        // PHPUnit 10 compatible way to test trigger_error().
+        set_error_handler(
+            function ($errno, $errstr): bool {
+                $this->assertSame(
+                    'Class `Redmine\Api\Project` will declared as final in v3.0.0, stop extending it.',
+                    $errstr,
+                );
+
+                restore_error_handler();
+                return true;
+            },
+            E_USER_DEPRECATED,
+        );
+
+        new class ($this->createStub(HttpClient::class)) extends Project {};
+    }
+
+    public function testConstructorTriggersDeprecationWarning(): void
+    {
+        // PHPUnit 10 compatible way to test trigger_error().
+        set_error_handler(
+            function ($errno, $errstr): bool {
+                $this->assertSame(
+                    'Method `Redmine\Api\Project::__construct()` is deprecated since v2.9.0 and will declared as private in v3.0.0, use `Redmine\Api\Project::fromHttpClient()` instead.',
+                    $errstr,
+                );
+
+                restore_error_handler();
+                return true;
+            },
+            E_USER_DEPRECATED,
+        );
+
+        new Project($this->createStub(HttpClient::class));
+    }
+
     /**
      * Test all().
      */
     public function testAllTriggersDeprecationWarning(): void
     {
-        $api = new Project(MockClient::create());
+        $api = Project::fromHttpClient($this->createStub(HttpClient::class));
 
         // PHPUnit 10 compatible way to test trigger_error().
         set_error_handler(
@@ -49,21 +87,21 @@ function ($errno, $errstr): bool {
     #[DataProvider('getAllData')]
     public function testAllReturnsClientGetResponse(string $response, string $responseType, $expectedResponse): void
     {
-        // Create the used mock objects
-        $client = $this->createMock(Client::class);
-        $client->expects($this->exactly(1))
-            ->method('requestGet')
-            ->with('/projects.json')
-            ->willReturn(true);
-        $client->expects($this->atLeast(1))
-            ->method('getLastResponseBody')
-            ->willReturn($response);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseContentType')
-            ->willReturn($responseType);
+        $client = AssertingHttpClient::create(
+            $this,
+            [
+                'GET',
+                '/projects.json',
+                'application/json',
+                '',
+                200,
+                $responseType,
+                $response,
+            ],
+        );
 
         // Create the object under test
-        $api = new Project($client);
+        $api = Project::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame($expectedResponse, $api->all());
@@ -88,26 +126,21 @@ public function testAllReturnsClientGetResponseWithParameters(): void
         $response = '["API Response"]';
         $expectedReturn = ['API Response'];
 
-        // Create the used mock objects
-        $client = $this->createMock(Client::class);
-        $client->expects($this->once())
-            ->method('requestGet')
-            ->with(
-                $this->logicalAnd(
-                    $this->stringStartsWith('/projects.json'),
-                    $this->stringContains('not-used'),
-                ),
-            )
-            ->willReturn(true);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseBody')
-            ->willReturn($response);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseContentType')
-            ->willReturn('application/json');
+        $client = AssertingHttpClient::create(
+            $this,
+            [
+                'GET',
+                '/projects.json?limit=25&offset=0&0=not-used',
+                'application/json',
+                '',
+                200,
+                'application/json',
+                $response,
+            ],
+        );
 
         // Create the object under test
-        $api = new Project($client);
+        $api = Project::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame($expectedReturn, $api->all($parameters));
@@ -125,23 +158,21 @@ public function testListingReturnsNameIdArray(): void
             'Project 5' => 5,
         ];
 
-        // Create the used mock objects
-        $client = $this->createMock(Client::class);
-        $client->expects($this->once())
-            ->method('requestGet')
-            ->with(
-                $this->stringStartsWith('/projects.json'),
-            )
-            ->willReturn(true);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseBody')
-            ->willReturn($response);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseContentType')
-            ->willReturn('application/json');
+        $client = AssertingHttpClient::create(
+            $this,
+            [
+                'GET',
+                '/projects.json',
+                'application/json',
+                '',
+                200,
+                'application/json',
+                $response,
+            ],
+        );
 
         // Create the object under test
-        $api = new Project($client);
+        $api = Project::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame($expectedReturn, $api->listing());
@@ -159,23 +190,21 @@ public function testListingCallsGetOnlyTheFirstTime(): void
             'Project 5' => 5,
         ];
 
-        // Create the used mock objects
-        $client = $this->createMock(Client::class);
-        $client->expects($this->once())
-            ->method('requestGet')
-            ->with(
-                $this->stringStartsWith('/projects.json'),
-            )
-            ->willReturn(true);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseBody')
-            ->willReturn($response);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseContentType')
-            ->willReturn('application/json');
+        $client = AssertingHttpClient::create(
+            $this,
+            [
+                'GET',
+                '/projects.json',
+                'application/json',
+                '',
+                200,
+                'application/json',
+                $response,
+            ],
+        );
 
         // Create the object under test
-        $api = new Project($client);
+        $api = Project::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame($expectedReturn, $api->listing());
@@ -194,23 +223,30 @@ public function testListingCallsGetEveryTimeWithForceUpdate(): void
             'Project 5' => 5,
         ];
 
-        // Create the used mock objects
-        $client = $this->createMock(Client::class);
-        $client->expects($this->exactly(2))
-            ->method('requestGet')
-            ->with(
-                $this->stringStartsWith('/projects.json'),
-            )
-            ->willReturn(true);
-        $client->expects($this->exactly(2))
-            ->method('getLastResponseBody')
-            ->willReturn($response);
-        $client->expects($this->exactly(2))
-            ->method('getLastResponseContentType')
-            ->willReturn('application/json');
+        $client = AssertingHttpClient::create(
+            $this,
+            [
+                'GET',
+                '/projects.json',
+                'application/json',
+                '',
+                200,
+                'application/json',
+                $response,
+            ],
+            [
+                'GET',
+                '/projects.json',
+                'application/json',
+                '',
+                200,
+                'application/json',
+                $response,
+            ],
+        );
 
         // Create the object under test
-        $api = new Project($client);
+        $api = Project::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame($expectedReturn, $api->listing(true));
@@ -222,15 +258,22 @@ public function testListingCallsGetEveryTimeWithForceUpdate(): void
      */
     public function testListingTriggersDeprecationWarning(): void
     {
-        $client = $this->createStub(Client::class);
-        $client->method('requestGet')
-            ->willReturn(true);
-        $client->method('getLastResponseBody')
-            ->willReturn('{"projects":[{"id":1,"name":"Project 1"},{"id":5,"name":"Project 5"}]}');
-        $client->method('getLastResponseContentType')
-            ->willReturn('application/json');
+        $response = '{"projects":[{"id":1,"name":"Project 1"},{"id":5,"name":"Project 5"}]}';
 
-        $api = new Project($client);
+        $client = AssertingHttpClient::create(
+            $this,
+            [
+                'GET',
+                '/projects.json',
+                'application/json',
+                '',
+                200,
+                'application/json',
+                $response,
+            ],
+        );
+
+        $api = Project::fromHttpClient($client);
 
         // PHPUnit 10 compatible way to test trigger_error().
         set_error_handler(
@@ -257,23 +300,21 @@ public function testGetIdByNameMakesGetRequest(): void
         // Test values
         $response = '{"projects":[{"id":5,"name":"Project 5"}]}';
 
-        // Create the used mock objects
-        $client = $this->createMock(Client::class);
-        $client->expects($this->once())
-            ->method('requestGet')
-            ->with(
-                $this->stringStartsWith('/projects.json'),
-            )
-            ->willReturn(true);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseBody')
-            ->willReturn($response);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseContentType')
-            ->willReturn('application/json');
+        $client = AssertingHttpClient::create(
+            $this,
+            [
+                'GET',
+                '/projects.json',
+                'application/json',
+                '',
+                200,
+                'application/json',
+                $response,
+            ],
+        );
 
         // Create the object under test
-        $api = new Project($client);
+        $api = Project::fromHttpClient($client);
 
         // Perform the tests
         $this->assertFalse($api->getIdByName('Project 1'));
@@ -282,15 +323,22 @@ public function testGetIdByNameMakesGetRequest(): void
 
     public function testGetIdByNameTriggersDeprecationWarning(): void
     {
-        $client = $this->createStub(Client::class);
-        $client->method('requestGet')
-            ->willReturn(true);
-        $client->method('getLastResponseBody')
-            ->willReturn('{"projects":[{"id":1,"name":"Project 1"},{"id":5,"name":"Project 5"}]}');
-        $client->method('getLastResponseContentType')
-            ->willReturn('application/json');
+        $response = '{"projects":[{"id":1,"name":"Project 1"},{"id":5,"name":"Project 5"}]}';
+
+        $client = AssertingHttpClient::create(
+            $this,
+            [
+                'GET',
+                '/projects.json',
+                'application/json',
+                '',
+                200,
+                'application/json',
+                $response,
+            ],
+        );
 
-        $api = new Project($client);
+        $api = Project::fromHttpClient($client);
 
         // PHPUnit 10 compatible way to test trigger_error().
         set_error_handler(
@@ -311,9 +359,9 @@ function ($errno, $errstr): bool {
 
     public function testDeprecatedPrepareParamsXml(): void
     {
-        $client = $this->createStub(Client::class);
+        $client = $this->createStub(HttpClient::class);
 
-        $api = new Project($client);
+        $api = Project::fromHttpClient($client);
 
         $method = new ReflectionMethod($api, 'prepareParamsXml');
         if (PHP_VERSION_ID < 80100) {
diff --git a/tests/Unit/Api/Query/FromHttpClientTest.php b/tests/Unit/Api/Query/FromHttpClientTest.php
new file mode 100644
index 00000000..8cc3e8fe
--- /dev/null
+++ b/tests/Unit/Api/Query/FromHttpClientTest.php
@@ -0,0 +1,21 @@
+<?php
+
+namespace Redmine\Tests\Unit\Api\Query;
+
+use PHPUnit\Framework\Attributes\CoversClass;
+use PHPUnit\Framework\TestCase;
+use Redmine\Api\Query;
+use Redmine\Http\HttpClient;
+
+#[CoversClass(Query::class)]
+class FromHttpClientTest extends TestCase
+{
+    public function testReturnsCorrectObject(): void
+    {
+        $httpClient = $this->createStub(HttpClient::class);
+
+        $api = Query::fromHttpClient($httpClient);
+
+        $this->assertInstanceOf(Query::class, $api);
+    }
+}
diff --git a/tests/Unit/Api/Query/ListTest.php b/tests/Unit/Api/Query/ListTest.php
index 4062c04e..70373ad7 100644
--- a/tests/Unit/Api/Query/ListTest.php
+++ b/tests/Unit/Api/Query/ListTest.php
@@ -7,6 +7,7 @@
 use Redmine\Api\Query;
 use Redmine\Client\Client;
 use Redmine\Exception\UnexpectedResponseException;
+use Redmine\Tests\Fixtures\AssertingHttpClient;
 
 #[CoversClass(Query::class)]
 class ListTest extends TestCase
@@ -17,21 +18,21 @@ public function testListWithoutParametersReturnsResponse(): void
         $response = '["API Response"]';
         $expectedReturn = ['API Response'];
 
-        // Create the used mock objects
-        $client = $this->createMock(Client::class);
-        $client->expects($this->once())
-            ->method('requestGet')
-            ->with('/queries.json')
-            ->willReturn(true);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseBody')
-            ->willReturn($response);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseContentType')
-            ->willReturn('application/json');
+        $client = AssertingHttpClient::create(
+            $this,
+            [
+                'GET',
+                '/queries.json',
+                'application/json',
+                '',
+                200,
+                'application/json',
+                $response,
+            ],
+        );
 
         // Create the object under test
-        $api = new Query($client);
+        $api = Query::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame($expectedReturn, $api->list());
@@ -44,21 +45,21 @@ public function testListWithParametersReturnsResponse(): void
         $response = '["API Response"]';
         $expectedReturn = ['API Response'];
 
-        // Create the used mock objects
-        $client = $this->createMock(Client::class);
-        $client->expects($this->any())
-            ->method('requestGet')
-            ->with('/queries.json?limit=25&offset=0&0=not-used')
-            ->willReturn(true);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseBody')
-            ->willReturn($response);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseContentType')
-            ->willReturn('application/json');
+        $client = AssertingHttpClient::create(
+            $this,
+            [
+                'GET',
+                '/queries.json?limit=25&offset=0&0=not-used',
+                'application/json',
+                '',
+                200,
+                'application/json',
+                $response,
+            ],
+        );
 
         // Create the object under test
-        $api = new Query($client);
+        $api = Query::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame($expectedReturn, $api->list($parameters));
@@ -66,21 +67,23 @@ public function testListWithParametersReturnsResponse(): void
 
     public function testListThrowsException(): void
     {
-        // Create the used mock objects
-        $client = $this->createMock(Client::class);
-        $client->expects($this->exactly(1))
-            ->method('requestGet')
-            ->with('/queries.json')
-            ->willReturn(true);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseBody')
-            ->willReturn('');
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseContentType')
-            ->willReturn('application/json');
+        $response = '';
+
+        $client = AssertingHttpClient::create(
+            $this,
+            [
+                'GET',
+                '/queries.json',
+                'application/json',
+                '',
+                200,
+                'application/json',
+                $response,
+            ],
+        );
 
         // Create the object under test
-        $api = new Query($client);
+        $api = Query::fromHttpClient($client);
 
         $this->expectException(UnexpectedResponseException::class);
         $this->expectExceptionMessage('The Redmine server replied with an unexpected response.');
diff --git a/tests/Unit/Api/QueryTest.php b/tests/Unit/Api/QueryTest.php
index 86af788c..93eb7b56 100644
--- a/tests/Unit/Api/QueryTest.php
+++ b/tests/Unit/Api/QueryTest.php
@@ -6,8 +6,8 @@
 use PHPUnit\Framework\Attributes\DataProvider;
 use PHPUnit\Framework\TestCase;
 use Redmine\Api\Query;
-use Redmine\Client\Client;
-use Redmine\Tests\Fixtures\MockClient;
+use Redmine\Http\HttpClient;
+use Redmine\Tests\Fixtures\AssertingHttpClient;
 
 /**
  * @author     Malte Gerth <mail@malte-gerth.de>
@@ -15,12 +15,50 @@
 #[CoversClass(Query::class)]
 class QueryTest extends TestCase
 {
+    public function testExtendingTheClassTriggersDeprecationWarning(): void
+    {
+        // PHPUnit 10 compatible way to test trigger_error().
+        set_error_handler(
+            function ($errno, $errstr): bool {
+                $this->assertSame(
+                    'Class `Redmine\Api\Query` will declared as final in v3.0.0, stop extending it.',
+                    $errstr,
+                );
+
+                restore_error_handler();
+                return true;
+            },
+            E_USER_DEPRECATED,
+        );
+
+        new class ($this->createStub(HttpClient::class)) extends Query {};
+    }
+
+    public function testConstructorTriggersDeprecationWarning(): void
+    {
+        // PHPUnit 10 compatible way to test trigger_error().
+        set_error_handler(
+            function ($errno, $errstr): bool {
+                $this->assertSame(
+                    'Method `Redmine\Api\Query::__construct()` is deprecated since v2.9.0 and will declared as private in v3.0.0, use `Redmine\Api\Query::fromHttpClient()` instead.',
+                    $errstr,
+                );
+
+                restore_error_handler();
+                return true;
+            },
+            E_USER_DEPRECATED,
+        );
+
+        new Query($this->createStub(HttpClient::class));
+    }
+
     /**
      * Test all().
      */
     public function testAllTriggersDeprecationWarning(): void
     {
-        $api = new Query(MockClient::create());
+        $api = Query::fromHttpClient($this->createStub(HttpClient::class));
 
         // PHPUnit 10 compatible way to test trigger_error().
         set_error_handler(
@@ -47,21 +85,21 @@ function ($errno, $errstr): bool {
     #[DataProvider('getAllData')]
     public function testAllReturnsClientGetResponse(string $response, string $responseType, $expectedResponse): void
     {
-        // Create the used mock objects
-        $client = $this->createMock(Client::class);
-        $client->expects($this->exactly(1))
-            ->method('requestGet')
-            ->with('/queries.json')
-            ->willReturn(true);
-        $client->expects($this->atLeast(1))
-            ->method('getLastResponseBody')
-            ->willReturn($response);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseContentType')
-            ->willReturn($responseType);
+        $client = AssertingHttpClient::create(
+            $this,
+            [
+                'GET',
+                '/queries.json',
+                'application/json',
+                '',
+                200,
+                $responseType,
+                $response,
+            ],
+        );
 
         // Create the object under test
-        $api = new Query($client);
+        $api = Query::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame($expectedResponse, $api->all());
@@ -86,26 +124,21 @@ public function testAllReturnsClientGetResponseWithParameters(): void
         $response = '["API Response"]';
         $expectedReturn = ['API Response'];
 
-        // Create the used mock objects
-        $client = $this->createMock(Client::class);
-        $client->expects($this->any())
-            ->method('requestGet')
-            ->with(
-                $this->logicalAnd(
-                    $this->stringStartsWith('/queries.json'),
-                    $this->stringContains('not-used'),
-                ),
-            )
-            ->willReturn(true);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseBody')
-            ->willReturn($response);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseContentType')
-            ->willReturn('application/json');
+        $client = AssertingHttpClient::create(
+            $this,
+            [
+                'GET',
+                '/queries.json?limit=25&offset=0&0=not-used',
+                'application/json',
+                '',
+                200,
+                'application/json',
+                $response,
+            ],
+        );
 
         // Create the object under test
-        $api = new Query($client);
+        $api = Query::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame($expectedReturn, $api->all($parameters));
diff --git a/tests/Unit/Api/Role/FromHttpClientTest.php b/tests/Unit/Api/Role/FromHttpClientTest.php
new file mode 100644
index 00000000..fdba6977
--- /dev/null
+++ b/tests/Unit/Api/Role/FromHttpClientTest.php
@@ -0,0 +1,21 @@
+<?php
+
+namespace Redmine\Tests\Unit\Api\Role;
+
+use PHPUnit\Framework\Attributes\CoversClass;
+use PHPUnit\Framework\TestCase;
+use Redmine\Api\Role;
+use Redmine\Http\HttpClient;
+
+#[CoversClass(Role::class)]
+class FromHttpClientTest extends TestCase
+{
+    public function testReturnsCorrectObject(): void
+    {
+        $httpClient = $this->createStub(HttpClient::class);
+
+        $api = Role::fromHttpClient($httpClient);
+
+        $this->assertInstanceOf(Role::class, $api);
+    }
+}
diff --git a/tests/Unit/Api/Role/ListNamesTest.php b/tests/Unit/Api/Role/ListNamesTest.php
index aa849d73..902eedc2 100644
--- a/tests/Unit/Api/Role/ListNamesTest.php
+++ b/tests/Unit/Api/Role/ListNamesTest.php
@@ -33,7 +33,7 @@ public function testListNamesReturnsCorrectResponse(string $expectedPath, int $r
         );
 
         // Create the object under test
-        $api = new Role($client);
+        $api = Role::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame($expectedResponse, $api->listNames());
@@ -98,7 +98,7 @@ public function testListNamesCallsHttpClientOnlyOnce(): void
         );
 
         // Create the object under test
-        $api = new Role($client);
+        $api = Role::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame([1 => 'Role 1'], $api->listNames());
diff --git a/tests/Unit/Api/Role/ListTest.php b/tests/Unit/Api/Role/ListTest.php
index 301e8054..bac61933 100644
--- a/tests/Unit/Api/Role/ListTest.php
+++ b/tests/Unit/Api/Role/ListTest.php
@@ -5,8 +5,8 @@
 use PHPUnit\Framework\Attributes\CoversClass;
 use PHPUnit\Framework\TestCase;
 use Redmine\Api\Role;
-use Redmine\Client\Client;
 use Redmine\Exception\UnexpectedResponseException;
+use Redmine\Tests\Fixtures\AssertingHttpClient;
 
 #[CoversClass(Role::class)]
 class ListTest extends TestCase
@@ -17,21 +17,21 @@ public function testListWithoutParametersReturnsResponse(): void
         $response = '["API Response"]';
         $expectedReturn = ['API Response'];
 
-        // Create the used mock objects
-        $client = $this->createMock(Client::class);
-        $client->expects($this->once())
-            ->method('requestGet')
-            ->with('/roles.json')
-            ->willReturn(true);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseBody')
-            ->willReturn($response);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseContentType')
-            ->willReturn('application/json');
+        $client = AssertingHttpClient::create(
+            $this,
+            [
+                'GET',
+                '/roles.json',
+                'application/json',
+                '',
+                200,
+                'application/json',
+                $response,
+            ],
+        );
 
         // Create the object under test
-        $api = new Role($client);
+        $api = Role::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame($expectedReturn, $api->list());
@@ -44,21 +44,21 @@ public function testListWithParametersReturnsResponse(): void
         $response = '["API Response"]';
         $expectedReturn = ['API Response'];
 
-        // Create the used mock objects
-        $client = $this->createMock(Client::class);
-        $client->expects($this->once())
-            ->method('requestGet')
-            ->with('/roles.json?limit=25&offset=0&0=not-used')
-            ->willReturn(true);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseBody')
-            ->willReturn($response);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseContentType')
-            ->willReturn('application/json');
+        $client = AssertingHttpClient::create(
+            $this,
+            [
+                'GET',
+                '/roles.json?limit=25&offset=0&0=not-used',
+                'application/json',
+                '',
+                200,
+                'application/json',
+                $response,
+            ],
+        );
 
         // Create the object under test
-        $api = new Role($client);
+        $api = Role::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame($expectedReturn, $api->list($parameters));
@@ -66,21 +66,23 @@ public function testListWithParametersReturnsResponse(): void
 
     public function testListThrowsException(): void
     {
-        // Create the used mock objects
-        $client = $this->createMock(Client::class);
-        $client->expects($this->exactly(1))
-            ->method('requestGet')
-            ->with('/roles.json')
-            ->willReturn(true);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseBody')
-            ->willReturn('');
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseContentType')
-            ->willReturn('application/json');
+        $response = '';
+
+        $client = AssertingHttpClient::create(
+            $this,
+            [
+                'GET',
+                '/roles.json',
+                'application/json',
+                '',
+                200,
+                'application/json',
+                $response,
+            ],
+        );
 
         // Create the object under test
-        $api = new Role($client);
+        $api = Role::fromHttpClient($client);
 
         $this->expectException(UnexpectedResponseException::class);
         $this->expectExceptionMessage('The Redmine server replied with an unexpected response.');
diff --git a/tests/Unit/Api/Role/ShowTest.php b/tests/Unit/Api/Role/ShowTest.php
index 7fba909c..4d12086f 100644
--- a/tests/Unit/Api/Role/ShowTest.php
+++ b/tests/Unit/Api/Role/ShowTest.php
@@ -31,7 +31,7 @@ public function testShowReturnsCorrectResponse($id, string $expectedPath, string
         );
 
         // Create the object under test
-        $api = new Role($client);
+        $api = Role::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame($expectedReturn, $api->show($id));
diff --git a/tests/Unit/Api/RoleTest.php b/tests/Unit/Api/RoleTest.php
index 249dba22..dd4b47c9 100644
--- a/tests/Unit/Api/RoleTest.php
+++ b/tests/Unit/Api/RoleTest.php
@@ -6,8 +6,8 @@
 use PHPUnit\Framework\Attributes\DataProvider;
 use PHPUnit\Framework\TestCase;
 use Redmine\Api\Role;
-use Redmine\Client\Client;
-use Redmine\Tests\Fixtures\MockClient;
+use Redmine\Http\HttpClient;
+use Redmine\Tests\Fixtures\AssertingHttpClient;
 
 /**
  * @author     Malte Gerth <mail@malte-gerth.de>
@@ -15,12 +15,50 @@
 #[CoversClass(Role::class)]
 class RoleTest extends TestCase
 {
+    public function testExtendingTheClassTriggersDeprecationWarning(): void
+    {
+        // PHPUnit 10 compatible way to test trigger_error().
+        set_error_handler(
+            function ($errno, $errstr): bool {
+                $this->assertSame(
+                    'Class `Redmine\Api\Role` will declared as final in v3.0.0, stop extending it.',
+                    $errstr,
+                );
+
+                restore_error_handler();
+                return true;
+            },
+            E_USER_DEPRECATED,
+        );
+
+        new class ($this->createStub(HttpClient::class)) extends Role {};
+    }
+
+    public function testConstructorTriggersDeprecationWarning(): void
+    {
+        // PHPUnit 10 compatible way to test trigger_error().
+        set_error_handler(
+            function ($errno, $errstr): bool {
+                $this->assertSame(
+                    'Method `Redmine\Api\Role::__construct()` is deprecated since v2.9.0 and will declared as private in v3.0.0, use `Redmine\Api\Role::fromHttpClient()` instead.',
+                    $errstr,
+                );
+
+                restore_error_handler();
+                return true;
+            },
+            E_USER_DEPRECATED,
+        );
+
+        new Role($this->createStub(HttpClient::class));
+    }
+
     /**
      * Test all().
      */
     public function testAllTriggersDeprecationWarning(): void
     {
-        $api = new Role(MockClient::create());
+        $api = Role::fromHttpClient($this->createStub(HttpClient::class));
 
         // PHPUnit 10 compatible way to test trigger_error().
         set_error_handler(
@@ -47,21 +85,21 @@ function ($errno, $errstr): bool {
     #[DataProvider('getAllData')]
     public function testAllReturnsClientGetResponse(string $response, string $responseType, $expectedResponse): void
     {
-        // Create the used mock objects
-        $client = $this->createMock(Client::class);
-        $client->expects($this->exactly(1))
-            ->method('requestGet')
-            ->with('/roles.json')
-            ->willReturn(true);
-        $client->expects($this->atLeast(1))
-            ->method('getLastResponseBody')
-            ->willReturn($response);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseContentType')
-            ->willReturn($responseType);
+        $client = AssertingHttpClient::create(
+            $this,
+            [
+                'GET',
+                '/roles.json',
+                'application/json',
+                '',
+                200,
+                'application/json',
+                $response,
+            ],
+        );
 
         // Create the object under test
-        $api = new Role($client);
+        $api = Role::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame($expectedResponse, $api->all());
@@ -86,26 +124,21 @@ public function testAllReturnsClientGetResponseWithParametersAndProject(): void
         $response = '["API Response"]';
         $expectedReturn = ['API Response'];
 
-        // Create the used mock objects
-        $client = $this->createMock(Client::class);
-        $client->expects($this->once())
-            ->method('requestGet')
-            ->with(
-                $this->logicalAnd(
-                    $this->stringStartsWith('/roles.json'),
-                    $this->stringContains('not-used'),
-                ),
-            )
-            ->willReturn(true);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseBody')
-            ->willReturn($response);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseContentType')
-            ->willReturn('application/json');
+        $client = AssertingHttpClient::create(
+            $this,
+            [
+                'GET',
+                '/roles.json?limit=25&offset=0&0=not-used',
+                'application/json',
+                '',
+                200,
+                'application/json',
+                $response,
+            ],
+        );
 
         // Create the object under test
-        $api = new Role($client);
+        $api = Role::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame($expectedReturn, $api->all($parameters));
@@ -123,23 +156,21 @@ public function testListingReturnsNameIdArray(): void
             'Role 5' => 5,
         ];
 
-        // Create the used mock objects
-        $client = $this->createMock(Client::class);
-        $client->expects($this->once())
-            ->method('requestGet')
-            ->with(
-                $this->stringStartsWith('/roles.json'),
-            )
-            ->willReturn(true);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseBody')
-            ->willReturn($response);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseContentType')
-            ->willReturn('application/json');
+        $client = AssertingHttpClient::create(
+            $this,
+            [
+                'GET',
+                '/roles.json',
+                'application/json',
+                '',
+                200,
+                'application/json',
+                $response,
+            ],
+        );
 
         // Create the object under test
-        $api = new Role($client);
+        $api = Role::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame($expectedReturn, $api->listing());
@@ -157,23 +188,21 @@ public function testListingCallsGetOnlyTheFirstTime(): void
             'Role 5' => 5,
         ];
 
-        // Create the used mock objects
-        $client = $this->createMock(Client::class);
-        $client->expects($this->once())
-            ->method('requestGet')
-            ->with(
-                $this->stringStartsWith('/roles.json'),
-            )
-            ->willReturn(true);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseBody')
-            ->willReturn($response);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseContentType')
-            ->willReturn('application/json');
+        $client = AssertingHttpClient::create(
+            $this,
+            [
+                'GET',
+                '/roles.json',
+                'application/json',
+                '',
+                200,
+                'application/json',
+                $response,
+            ],
+        );
 
         // Create the object under test
-        $api = new Role($client);
+        $api = Role::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame($expectedReturn, $api->listing());
@@ -192,23 +221,30 @@ public function testListingCallsGetEveryTimeWithForceUpdate(): void
             'Role 5' => 5,
         ];
 
-        // Create the used mock objects
-        $client = $this->createMock(Client::class);
-        $client->expects($this->exactly(2))
-            ->method('requestGet')
-            ->with(
-                $this->stringStartsWith('/roles.json'),
-            )
-            ->willReturn(true);
-        $client->expects($this->exactly(2))
-            ->method('getLastResponseBody')
-            ->willReturn($response);
-        $client->expects($this->exactly(2))
-            ->method('getLastResponseContentType')
-            ->willReturn('application/json');
+        $client = AssertingHttpClient::create(
+            $this,
+            [
+                'GET',
+                '/roles.json',
+                'application/json',
+                '',
+                200,
+                'application/json',
+                $response,
+            ],
+            [
+                'GET',
+                '/roles.json',
+                'application/json',
+                '',
+                200,
+                'application/json',
+                $response,
+            ],
+        );
 
         // Create the object under test
-        $api = new Role($client);
+        $api = Role::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame($expectedReturn, $api->listing(true));
@@ -220,15 +256,22 @@ public function testListingCallsGetEveryTimeWithForceUpdate(): void
      */
     public function testListingTriggersDeprecationWarning(): void
     {
-        $client = $this->createStub(Client::class);
-        $client->method('requestGet')
-            ->willReturn(true);
-        $client->method('getLastResponseBody')
-            ->willReturn('{"roles":[{"id":1,"name":"Role 1"},{"id":5,"name":"Role 5"}]}');
-        $client->method('getLastResponseContentType')
-            ->willReturn('application/json');
-
-        $api = new Role($client);
+        $response = '{"roles":[{"id":1,"name":"Role 1"},{"id":5,"name":"Role 5"}]}';
+
+        $client = AssertingHttpClient::create(
+            $this,
+            [
+                'GET',
+                '/roles.json',
+                'application/json',
+                '',
+                200,
+                'application/json',
+                $response,
+            ],
+        );
+
+        $api = Role::fromHttpClient($client);
 
         // PHPUnit 10 compatible way to test trigger_error().
         set_error_handler(
diff --git a/tests/Unit/Api/Search/FromHttpClientTest.php b/tests/Unit/Api/Search/FromHttpClientTest.php
new file mode 100644
index 00000000..63340a93
--- /dev/null
+++ b/tests/Unit/Api/Search/FromHttpClientTest.php
@@ -0,0 +1,21 @@
+<?php
+
+namespace Redmine\Tests\Unit\Api\Search;
+
+use PHPUnit\Framework\Attributes\CoversClass;
+use PHPUnit\Framework\TestCase;
+use Redmine\Api\Search;
+use Redmine\Http\HttpClient;
+
+#[CoversClass(Search::class)]
+class FromHttpClientTest extends TestCase
+{
+    public function testReturnsCorrectObject(): void
+    {
+        $httpClient = $this->createStub(HttpClient::class);
+
+        $api = Search::fromHttpClient($httpClient);
+
+        $this->assertInstanceOf(Search::class, $api);
+    }
+}
diff --git a/tests/Unit/Api/Search/ListByQueryTest.php b/tests/Unit/Api/Search/ListByQueryTest.php
index 02848dcb..319c3101 100644
--- a/tests/Unit/Api/Search/ListByQueryTest.php
+++ b/tests/Unit/Api/Search/ListByQueryTest.php
@@ -7,6 +7,7 @@
 use Redmine\Api\Search;
 use Redmine\Client\Client;
 use Redmine\Exception\UnexpectedResponseException;
+use Redmine\Tests\Fixtures\AssertingHttpClient;
 
 #[CoversClass(Search::class)]
 class ListByQueryTest extends TestCase
@@ -17,21 +18,21 @@ public function testListByQueryWithoutParametersReturnsResponse(): void
         $response = '["API Response"]';
         $expectedReturn = ['API Response'];
 
-        // Create the used mock objects
-        $client = $this->createMock(Client::class);
-        $client->expects($this->once())
-            ->method('requestGet')
-            ->with('/search.json?limit=25&offset=0&q=query')
-            ->willReturn(true);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseBody')
-            ->willReturn($response);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseContentType')
-            ->willReturn('application/json');
+        $client = AssertingHttpClient::create(
+            $this,
+            [
+                'GET',
+                '/search.json?limit=25&offset=0&q=query',
+                'application/json',
+                '',
+                200,
+                'application/json',
+                $response,
+            ],
+        );
 
         // Create the object under test
-        $api = new Search($client);
+        $api = Search::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame($expectedReturn, $api->listByQuery('query'));
@@ -44,21 +45,21 @@ public function testListByQueryWithParametersReturnsResponse(): void
         $response = '["API Response"]';
         $expectedReturn = ['API Response'];
 
-        // Create the used mock objects
-        $client = $this->createMock(Client::class);
-        $client->expects($this->any())
-            ->method('requestGet')
-            ->with('/search.json?limit=25&offset=0&0=not-used&q=query')
-            ->willReturn(true);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseBody')
-            ->willReturn($response);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseContentType')
-            ->willReturn('application/json');
+        $client = AssertingHttpClient::create(
+            $this,
+            [
+                'GET',
+                '/search.json?limit=25&offset=0&0=not-used&q=query',
+                'application/json',
+                '',
+                200,
+                'application/json',
+                $response,
+            ],
+        );
 
         // Create the object under test
-        $api = new Search($client);
+        $api = Search::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame($expectedReturn, $api->listByQuery('query', $parameters));
@@ -66,21 +67,23 @@ public function testListByQueryWithParametersReturnsResponse(): void
 
     public function testListByQueryThrowsException(): void
     {
-        // Create the used mock objects
-        $client = $this->createMock(Client::class);
-        $client->expects($this->exactly(1))
-            ->method('requestGet')
-            ->with('/search.json?limit=25&offset=0&q=query')
-            ->willReturn(true);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseBody')
-            ->willReturn('');
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseContentType')
-            ->willReturn('application/json');
+        $response = '';
+
+        $client = AssertingHttpClient::create(
+            $this,
+            [
+                'GET',
+                '/search.json?limit=25&offset=0&q=query',
+                'application/json',
+                '',
+                200,
+                'application/json',
+                $response,
+            ],
+        );
 
         // Create the object under test
-        $api = new Search($client);
+        $api = Search::fromHttpClient($client);
 
         $this->expectException(UnexpectedResponseException::class);
         $this->expectExceptionMessage('The Redmine server replied with an unexpected response.');
diff --git a/tests/Unit/Api/Search/SearchTest.php b/tests/Unit/Api/Search/SearchTest.php
index 5756a619..56255621 100644
--- a/tests/Unit/Api/Search/SearchTest.php
+++ b/tests/Unit/Api/Search/SearchTest.php
@@ -7,14 +7,15 @@
 use PHPUnit\Framework\TestCase;
 use Redmine\Api\Search;
 use Redmine\Client\Client;
-use Redmine\Tests\Fixtures\MockClient;
+use Redmine\Http\HttpClient;
+use Redmine\Tests\Fixtures\AssertingHttpClient;
 
 #[CoversClass(Search::class)]
 class SearchTest extends TestCase
 {
     public function testSearchTriggersDeprecationWarning(): void
     {
-        $api = new Search(MockClient::create());
+        $api = Search::fromHttpClient($this->createStub(HttpClient::class));
 
         // PHPUnit 10 compatible way to test trigger_error().
         set_error_handler(
@@ -39,21 +40,21 @@ function ($errno, $errstr): bool {
     #[DataProvider('getAllData')]
     public function testSearchReturnsClientGetResponse(string $response, string $responseType, $expectedResponse): void
     {
-        // Create the used mock objects
-        $client = $this->createMock(Client::class);
-        $client->expects($this->exactly(1))
-            ->method('requestGet')
-            ->with('/search.json?limit=25&offset=0&q=query')
-            ->willReturn(true);
-        $client->expects($this->atLeast(1))
-            ->method('getLastResponseBody')
-            ->willReturn($response);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseContentType')
-            ->willReturn($responseType);
+        $client = AssertingHttpClient::create(
+            $this,
+            [
+                'GET',
+                '/search.json?limit=25&offset=0&q=query',
+                'application/json',
+                '',
+                200,
+                $responseType,
+                $response,
+            ],
+        );
 
         // Create the object under test
-        $api = new Search($client);
+        $api = Search::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame($expectedResponse, $api->search('query'));
@@ -75,21 +76,21 @@ public function testSearchReturnsClientGetResponseWithParameters(): void
         $response = '["API Response"]';
         $expectedReturn = ['API Response'];
 
-        // Create the used mock objects
-        $client = $this->createMock(Client::class);
-        $client->expects($this->any())
-            ->method('requestGet')
-            ->with('/search.json?limit=25&offset=0&0=not-used&q=query')
-            ->willReturn(true);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseBody')
-            ->willReturn($response);
-        $client->expects($this->exactly(1))
-            ->method('getLastResponseContentType')
-            ->willReturn('application/json');
+        $client = AssertingHttpClient::create(
+            $this,
+            [
+                'GET',
+                '/search.json?limit=25&offset=0&0=not-used&q=query',
+                'application/json',
+                '',
+                200,
+                'application/json',
+                $response,
+            ],
+        );
 
         // Create the object under test
-        $api = new Search($client);
+        $api = Search::fromHttpClient($client);
 
         // Perform the tests
         $this->assertSame($expectedReturn, $api->search('query', $parameters));
diff --git a/tests/Unit/Api/SearchTest.php b/tests/Unit/Api/SearchTest.php
new file mode 100644
index 00000000..498de836
--- /dev/null
+++ b/tests/Unit/Api/SearchTest.php
@@ -0,0 +1,50 @@
+<?php
+
+namespace Redmine\Tests\Unit\Api;
+
+use PHPUnit\Framework\Attributes\CoversClass;
+use PHPUnit\Framework\TestCase;
+use Redmine\Api\Search;
+use Redmine\Http\HttpClient;
+
+#[CoversClass(Search::class)]
+class SearchTest extends TestCase
+{
+    public function testExtendingTheClassTriggersDeprecationWarning(): void
+    {
+        // PHPUnit 10 compatible way to test trigger_error().
+        set_error_handler(
+            function ($errno, $errstr): bool {
+                $this->assertSame(
+                    'Class `Redmine\Api\Search` will declared as final in v3.0.0, stop extending it.',
+                    $errstr,
+                );
+
+                restore_error_handler();
+                return true;
+            },
+            E_USER_DEPRECATED,
+        );
+
+        new class ($this->createStub(HttpClient::class)) extends Search {};
+    }
+
+    public function testConstructorTriggersDeprecationWarning(): void
+    {
+        // PHPUnit 10 compatible way to test trigger_error().
+        set_error_handler(
+            function ($errno, $errstr): bool {
+                $this->assertSame(
+                    'Method `Redmine\Api\Search::__construct()` is deprecated since v2.9.0 and will declared as private in v3.0.0, use `Redmine\Api\Search::fromHttpClient()` instead.',
+                    $errstr,
+                );
+
+                restore_error_handler();
+                return true;
+            },
+            E_USER_DEPRECATED,
+        );
+
+        new Search($this->createStub(HttpClient::class));
+    }
+}
diff --git a/tests/Unit/Client/NativeCurlClientTest.php b/tests/Unit/Client/NativeCurlClientTest.php
index bd0c03f5..e9b24471 100644
--- a/tests/Unit/Client/NativeCurlClientTest.php
+++ b/tests/Unit/Client/NativeCurlClientTest.php
@@ -966,7 +966,7 @@ public function testCurlErrorThrowsException(): void
      * @dataProvider getApiClassesProvider
      */
     #[DataProvider('getApiClassesProvider')]
-    public function testGetApiShouldReturnApiInstance(string $apiName, string $class): void
+    public function testGetApiReturnsApiInstance(string $apiName, string $class): void
     {
         $client = new NativeCurlClient(
             'http://test.local',
@@ -1001,7 +1001,24 @@ public static function getApiClassesProvider(): array
         ];
     }
 
-    public function testGetApiShouldThrowException(): void
+    /**
+     * @dataProvider getApiClassesProvider
+     */
+    #[DataProvider('getApiClassesProvider')]
+    public function testGetApiOnMultipleCallsReturnSameApiInstance(string $apiName, string $class): void
+    {
+        $client = new NativeCurlClient(
+            'http://test.local',
+            'access_token',
+        );
+
+        $this->assertSame(
+            $client->getApi($apiName),
+            $client->getApi($apiName),
+        );
+    }
+
+    public function testGetApiWithInvalidApiThrowsException(): void
     {
         $client = new NativeCurlClient(
             'http://test.local',