Fatal error: Uncaught Error: Class "PHPUnit\Framework\TestCase" not found in /home/peekizt/www/vendor/markrogoyski/math-php/tests/Number/QuaternionAxiomsTest.php:21 Stack trace: #0 {main} thrown in /home/peekizt/www/vendor/markrogoyski/math-php/tests/Number/QuaternionAxiomsTest.php on line 21