Fatal error: Uncaught Error: Class "Tests\TestCase" not found in C:\xampp\htdocs\RegnowSite\vendor\topthink\think-helper\tests\StrTest.php:6 Stack trace: #0 {main} thrown in C:\xampp\htdocs\RegnowSite\vendor\topthink\think-helper\tests\StrTest.php on line 6