Fatal error: Uncaught Error: Class "Flarum\Testing\integration\TestCase" not found in /opt/lampp/htdocs/forum/flarum/vendor/fof/oauth/tests/integration/api/ForumSerializerTest.php:18 Stack trace: #0 {main} thrown in /opt/lampp/htdocs/forum/flarum/vendor/fof/oauth/tests/integration/api/ForumSerializerTest.php on line 18