Fatal error: Uncaught Error: Class "PHPUnit\Framework\TestCase" not found in I:\www\pvcTestingUtils\src\testingTraits\MockNonNegativeIntegerValidatorFactory.php:17 Stack trace: #0 {main} thrown in I:\www\pvcTestingUtils\src\testingTraits\MockNonNegativeIntegerValidatorFactory.php on line 17