Fatal error: Uncaught Error: Class "PHPUnit\Framework\TestCase" not found in /var/www/html/dev.hallescherfc.de/vendor/typo3/cms-composer-installers/tests/Plugin/Util/ExtensionKeyResolverTest.php:23 Stack trace: #0 {main} thrown in /var/www/html/dev.hallescherfc.de/vendor/typo3/cms-composer-installers/tests/Plugin/Util/ExtensionKeyResolverTest.php on line 23