Fatal error: Uncaught Error: Class 'PHPUnit\Framework\TestCase' not found in E:\xampp\htdocs\key1\vendor\symfony\event-dispatcher\Tests\Debug\TraceableEventDispatcherTest.php:23 Stack trace: #0 {main} thrown in E:\xampp\htdocs\key1\vendor\symfony\event-dispatcher\Tests\Debug\TraceableEventDispatcherTest.php on line 23