test: re-register fixture post types between tests

EdgeCaseTest::testUnregisteredCptDoesNotHijackQuery calls
unregister_post_type('book') without re-registering. Mantle's
Preserves_Globals backs up $wp_post_types but not $_wp_post_type_features,
so post_type_supports('book', 'title') stayed false for subsequent tests.
TSF's get_post_title then short-circuited and the breadcrumb fell back to
"Untitled", flaking AutodescriptionTest::testBreadcrumbsOnSinglePostIncludesPfcptPage
depending on test order.

Extracts the post type registration into TestCase::registerFixturePostTypes()
and calls it from both bootstrap.php and createFixtures() so the features
global is rebuilt before any test that needs it.

Author: nlemoine

tests/Fixtures/TestCase.php

@@ -58,6 +58,13 @@ protected function setUp(): void
      */
     protected function createFixtures(): void
     {
+        // Mantle's Preserves_Globals trait backs up $wp_post_types between tests
+        // but not $_wp_post_type_features. When a test calls unregister_post_type()
+        // without re-registering (e.g. EdgeCaseTest::testUnregisteredCptDoesNotHijackQuery),
+        // post_type_supports() returns false for subsequent tests and downstream
+        // code (TSF's get_post_title, etc.) falls back to defaults like "Untitled".
+        self::registerFixturePostTypes();
+
         $this->createBooks();
         $this->createBikes();
         $this->createHomePages();
@@ -79,6 +86,39 @@ protected function createFixtures(): void
         flush_rewrite_rules();
     }
 
+    /**
+     * Register the fixture post types (book, bike).
+     *
+     * Called from bootstrap.php on suite startup and from createFixtures()
+     * to guard against tests that leave post types unregistered.
+     */
+    public static function registerFixturePostTypes(): void
+    {
+        $postTypes = [
+            self::BIKE_POST_TYPE => [
+                'public' => true,
+                'publicly_queryable' => true,
+                'label' => 'Bikes',
+                'has_archive' => true,
+                'rewrite' => ['slug' => 'bikes'],
+            ],
+            self::BOOK_POST_TYPE => [
+                'public' => true,
+                'publicly_queryable' => true,
+                'label' => 'Books',
+                'has_archive' => true,
+                'rewrite' => ['slug' => 'books'],
+            ],
+        ];
+
+        foreach ($postTypes as $postType => $args) {
+            if (post_type_exists($postType)) {
+                unregister_post_type($postType);
+            }
+            register_post_type($postType, $args);
+        }
+    }
+
     /**
      * Create book posts with a genre taxonomy term.
      *

tests/bootstrap.php

@@ -2,6 +2,8 @@
 
 declare(strict_types=1);
 
+use n5s\PageForCustomPostType\Tests\Fixtures\TestCase;
+
 use function Mantle\Testing\manager;
 
 require_once __DIR__ . '/../vendor/autoload.php';
@@ -35,24 +37,7 @@
         }
     })
     ->init(static function (): void {
-        register_post_type('bike', [
-            'public' => true,
-            'publicly_queryable' => true,
-            'label' => 'Bikes',
-            'has_archive' => true,
-            'rewrite' => [
-                'slug' => 'bikes',
-            ],
-        ]);
-        register_post_type('book', [
-            'public' => true,
-            'publicly_queryable' => true,
-            'label' => 'Books',
-            'has_archive' => true,
-            'rewrite' => [
-                'slug' => 'books',
-            ],
-        ]);
+        TestCase::registerFixturePostTypes();
         register_taxonomy('genre', 'book', [
             'public' => true,
             'label' => 'Genres',