Fatal error: Uncaught Error: Class "PHPUnit\Framework\TestCase" not found in C:\xampp\htdocs\astra-backoffice\vendor\symfony\mailer\Tests\Transport\Smtp\SmtpTransportTest.php:31 Stack trace: #0 {main} thrown in C:\xampp\htdocs\astra-backoffice\vendor\symfony\mailer\Tests\Transport\Smtp\SmtpTransportTest.php on line 31