Fatal error: Uncaught Error: Class "PHPUnit\Framework\TestCase" not found in D:\xampp\htdocs\_runing\sales-manager-system\vendor\laravel\framework\src\Illuminate\Foundation\Testing\TestCase.php:8 Stack trace: #0 {main} thrown in D:\xampp\htdocs\_runing\sales-manager-system\vendor\laravel\framework\src\Illuminate\Foundation\Testing\TestCase.php on line 8