Fatal error: Uncaught Error: Class "PHPUnit\Framework\TestCase" not found in /var/www/usonboard.com/vendor/guzzlehttp/promises/tests/RejectionExceptionTest.php:13 Stack trace: #0 {main} thrown in /var/www/usonboard.com/vendor/guzzlehttp/promises/tests/RejectionExceptionTest.php on line 13