Fatal error: Uncaught Error: Class "PHPUnit\Framework\TestCase" not found in /var/www/html/ilias/components/ILIAS/OnScreenChat/tests/ilOnScreenChatBaseTestCase.php:27 Stack trace: #0 {main} thrown in /var/www/html/ilias/components/ILIAS/OnScreenChat/tests/ilOnScreenChatBaseTestCase.php on line 27