Fatal error: Uncaught Error: Class 'PHPUnit\Framework\TestCase' not found in E:\xampp\htdocs\www\key1\vendor\sebastian\recursion-context\tests\ContextTest.php:18 Stack trace: #0 {main} thrown in E:\xampp\htdocs\www\key1\vendor\sebastian\recursion-context\tests\ContextTest.php on line 18