Fatal error: Uncaught Error: Class "PHPUnit\Framework\TestCase" not found in /opt/lampp/htdocs/tsiasset/vendor/phpoffice/math/tests/Math/Element/SemanticsTest.php:10 Stack trace: #0 {main} thrown in /opt/lampp/htdocs/tsiasset/vendor/phpoffice/math/tests/Math/Element/SemanticsTest.php on line 10