Fatal error: Uncaught Error: Class "PHPUnit\Framework\TestCase" not found in C:\Apache24\htdocs\cms_upgrade\vendor\paragonie\hidden-string\test\HiddenStringTest.php:9 Stack trace: #0 {main} thrown in C:\Apache24\htdocs\cms_upgrade\vendor\paragonie\hidden-string\test\HiddenStringTest.php on line 9