Fatal error: Uncaught Error: Class 'PHPUnit\Framework\TestCase' not found in C:\xampp\htdocs\dpbb\vendor\paragonie\constant_time_encoding\tests\RFC4648Test.php:15 Stack trace: #0 {main} thrown in C:\xampp\htdocs\dpbb\vendor\paragonie\constant_time_encoding\tests\RFC4648Test.php on line 15