Fatal error: Uncaught Error: Class "PHPUnit\Framework\TestCase" not found in C:\Apache24\htdocs\laravelcurso\vendor\sebastian\environment\tests\OperatingSystemTest.php:20 Stack trace: #0 {main} thrown in C:\Apache24\htdocs\laravelcurso\vendor\sebastian\environment\tests\OperatingSystemTest.php on line 20