Fatal error: Uncaught Error: Class "PHPUnit\Framework\TestCase" not found in C:\xampp\htdocs\astra-backoffice\vendor\league\commonmark\tests\functional\Extension\Strikethrough\StrikethroughExtensionTest.php:23 Stack trace: #0 {main} thrown in C:\xampp\htdocs\astra-backoffice\vendor\league\commonmark\tests\functional\Extension\Strikethrough\StrikethroughExtensionTest.php on line 23