Fatal error: Uncaught Error: Class "PHPUnit\Framework\TestCase" not found in /home/mulwnet/beta.mulw.net/vendor/symfony/mime/Tests/Header/MailboxListHeaderTest.php:18 Stack trace: #0 {main} thrown in /home/mulwnet/beta.mulw.net/vendor/symfony/mime/Tests/Header/MailboxListHeaderTest.php on line 18