Fatal error: Uncaught Error: Class "PHPUnit\Framework\TestCase" not found in C:\xampp\htdocs\londoncityroom\vendor\nicmart\tree\test\Unit\Node\NodeTest.php:25 Stack trace: #0 {main} thrown in C:\xampp\htdocs\londoncityroom\vendor\nicmart\tree\test\Unit\Node\NodeTest.php on line 25