Fatal error: Uncaught Error: Class 'PHPUnit\Framework\TestCase' not found in E:\xampp\htdocs\www\yunwei\qr251\vendor\symfony\mailer\Test\TransportFactoryTestCase.php:29 Stack trace: #0 {main} thrown in E:\xampp\htdocs\www\yunwei\qr251\vendor\symfony\mailer\Test\TransportFactoryTestCase.php on line 29