Fatal error: Uncaught Error: Class "Tests\TestCase" not found in C:\xampp\htdocs\snipe-it\tests\Feature\Notifications\Webhooks\SlackNotificationsUponCheckoutTest.php:24 Stack trace: #0 {main} thrown in C:\xampp\htdocs\snipe-it\tests\Feature\Notifications\Webhooks\SlackNotificationsUponCheckoutTest.php on line 24