Fatal error: Uncaught Error: Class "Tests\DuskTestCase" not found in C:\xampp\htdocs\datatablecolcolor\Laravel-Datatables-Column-Colors\tests\Browser\CustomersTest.php:9 Stack trace: #0 {main} thrown in C:\xampp\htdocs\datatablecolcolor\Laravel-Datatables-Column-Colors\tests\Browser\CustomersTest.php on line 9