Fatal error: Uncaught Error: Class "PHPUnit\Framework\TestCase" not found in C:\xampp\htdocs\www\zdxnew\web\vendor\apimatic\jsonmapper\tests\namespacetest\NamespaceTest.php:21 Stack trace: #0 {main} thrown in C:\xampp\htdocs\www\zdxnew\web\vendor\apimatic\jsonmapper\tests\namespacetest\NamespaceTest.php on line 21