Fatal error: Uncaught Error: Class 'PHPUnit\Framework\TestCase' not found in E:\xampp\htdocs\www\key2\vendor\symfony\process\Tests\ProcessUtilsTest.php:20 Stack trace: #0 {main} thrown in E:\xampp\htdocs\www\key2\vendor\symfony\process\Tests\ProcessUtilsTest.php on line 20