Fatal error: Uncaught Error: Class "PHPUnit\Framework\TestCase" not found in C:\xampp\htdocs\CnVideosSite\vendor\topthink\think-helper\tests\TestCase.php:11 Stack trace: #0 {main} thrown in C:\xampp\htdocs\CnVideosSite\vendor\topthink\think-helper\tests\TestCase.php on line 11