Fatal error: Uncaught Error: Class "PHPUnit\Framework\TestCase" not found in C:\xampp\htdocs\astra-backoffice\vendor\guzzlehttp\promises\tests\IsTest.php:13 Stack trace: #0 {main} thrown in C:\xampp\htdocs\astra-backoffice\vendor\guzzlehttp\promises\tests\IsTest.php on line 13