Fatal error: Uncaught Error: Class "PHPUnit\Framework\Constraint\Constraint" not found in /opt/lampp/htdocs/forum/flarum/vendor/symfony/http-foundation/Test/Constraint/ResponseFormatSame.php:23 Stack trace: #0 {main} thrown in /opt/lampp/htdocs/forum/flarum/vendor/symfony/http-foundation/Test/Constraint/ResponseFormatSame.php on line 23