Fatal error: Uncaught Error: Class "PHPUnit\Framework\TestCase" not found in /var/www/html/w/vendor/michelf/php-markdown/test/unit/MarkdownExtraTest.php:3 Stack trace: #0 {main} thrown in /var/www/html/w/vendor/michelf/php-markdown/test/unit/MarkdownExtraTest.php on line 3