refactor: make accept header content type preserving more robust

Author: alexzarbn

src/Http/Middleware/EnforceExpectsJson.php

@@ -3,6 +3,7 @@
 namespace Orion\Http\Middleware;
 
 use Illuminate\Http\Request;
+use Illuminate\Support\Str;
 
 class EnforceExpectsJson
 {
@@ -13,8 +14,8 @@ class EnforceExpectsJson
      */
     public function handle(Request $request, $next)
     {
-        if (strpos($request->header('Accept'), 'application/json') !== 0) {
-            $request->headers->add(['Accept' => 'application/json,' . $request->header('Accept')]);
+        if (!Str::contains($request->header('Accept'), 'application/json')) {
+            $request->headers->set('Accept', 'application/json, ' . $request->header('Accept'));
         }
 
         return $next($request);

tests/Unit/Http/Middleware/EnforceExpectsJsonTest.php

@@ -9,7 +9,7 @@
 class EnforceExpectsJsonTest extends TestCase
 {
     /** @test */
-    public function adding_accept_header()
+    public function adding_application_json_to_accept_header(): void
     {
         $request = Request::create('/api/posts');
 
@@ -20,4 +20,18 @@ function ($processedRequest) {
             }
         );
     }
+
+    /** @test */
+    public function preserving_existing_accept_header_content_types(): void
+    {
+        $request = Request::create('/api/posts');
+        $request->headers->set('Accept', 'application/xml');
+
+        (new EnforceExpectsJson())->handle(
+            $request,
+            function ($processedRequest) {
+                $this->assertSame('application/json, application/xml', $processedRequest->header('Accept'));
+            }
+        );
+    }
 }