Fatal error: Uncaught Error: Class "PHPUnit\Framework\TestCase" not found in C:\xampp\htdocs\cms-propay\vendor\webklex\php-imap\tests\ClientManagerTest.php:21 Stack trace: #0 {main} thrown in C:\xampp\htdocs\cms-propay\vendor\webklex\php-imap\tests\ClientManagerTest.php on line 21