Fatal error: Uncaught Error: Class "PHPUnit\Framework\TestCase" not found in /opt/lampp/htdocs/forum/flarum/vendor/symfony/service-contracts/Test/ServiceLocatorTestCase.php:20 Stack trace: #0 {main} thrown in /opt/lampp/htdocs/forum/flarum/vendor/symfony/service-contracts/Test/ServiceLocatorTestCase.php on line 20