Fatal error: Uncaught Error: Class "PHPUnit\Framework\TestCase" not found in D:\Application\www\E-Tracking\vendor\symfony\event-dispatcher\Tests\ImmutableEventDispatcherTest.php:21 Stack trace: #0 {main} thrown in D:\Application\www\E-Tracking\vendor\symfony\event-dispatcher\Tests\ImmutableEventDispatcherTest.php on line 21