Fatal error: Uncaught Error: Class 'PHPUnit\Framework\TestCase' not found in E:\xampp\htdocs\key1\vendor\sebastian\comparator\tests\MockObjectComparatorTest.php:23 Stack trace: #0 {main} thrown in E:\xampp\htdocs\key1\vendor\sebastian\comparator\tests\MockObjectComparatorTest.php on line 23