Fatal error: Uncaught Error: Class 'PHPUnit\Framework\TestCase' not found in /mnt/www/fss/service-center/vendor/guzzlehttp/psr7/tests/BaseTest.php:7 Stack trace: #0 {main} thrown in /mnt/www/fss/service-center/vendor/guzzlehttp/psr7/tests/BaseTest.php on line 7