fix: response headers are not required by default (#88)

Author: camilledejoye

src/PSR7/Validators/HeadersValidator.php

@@ -4,7 +4,6 @@
 
 namespace League\OpenAPIValidation\PSR7\Validators;
 
-use GuzzleHttp\Psr7\Response;
 use League\OpenAPIValidation\PSR7\Exception\Validation\InvalidHeaders;
 use League\OpenAPIValidation\PSR7\MessageValidator;
 use League\OpenAPIValidation\PSR7\OperationAddress;
@@ -34,7 +33,7 @@ public function validate(OperationAddress $addr, MessageInterface $message) : vo
 
         // Check if message misses required headers
         foreach ($headerSpecs as $header => $spec) {
-            if (($message instanceof Response || $spec->required) && ! $message->hasHeader($header)) {
+            if ($spec->required && ! $message->hasHeader($header)) {
                 throw InvalidHeaders::becauseOfMissingRequiredHeader($header, $addr);
             }
 

tests/PSR7/ValidateResponseTest.php

@@ -68,11 +68,11 @@ public function testItValidatesMessageWrongHeaderValueRed() : void
     {
         $addr = new OperationAddress('/path1', 'get');
 
-        $response = $this->makeGoodResponse('/path1', 'get')->withHeader('Header-B', 'wrong value');
+        $response = $this->makeGoodResponse('/path1', 'get')->withHeader('Header-C', 'wrong value');
 
         $this->expectException(InvalidHeaders::class);
         $this->expectExceptionMessage(
-            'Value "wrong value" for header "Header-B" is invalid for Response [get /path1 200]'
+            'Value "wrong value" for header "Header-C" is invalid for Response [get /path1 200]'
         );
 
         $validator = (new ValidatorBuilder())->fromYamlFile($this->apiSpecFile)->getResponseValidator();

tests/stubs/api.yaml

@@ -89,6 +89,7 @@ paths:
           description: posted
           headers:
             Set-Cookie:
+              required: true
               schema:
                 type: string
           content:
@@ -106,6 +107,13 @@ paths:
           description: fake endpoint
           headers:
             Header-B:
+              required: true
+              schema:
+                type: string
+                enum:
+                  - good value
+                  - another good value
+            Header-C:
               schema:
                 type: string
                 enum: