Fatal error: Uncaught Error: Class 'PHPUnit\Framework\TestCase' not found in D:\xampp\htdocs\psp\backend\vendor\lcobucci\jwt\test\functional\RFC6978VectorTest.php:15 Stack trace: #0 {main} thrown in D:\xampp\htdocs\psp\backend\vendor\lcobucci\jwt\test\functional\RFC6978VectorTest.php on line 15