Fatal error: Uncaught Error: Class "PHPUnit\Framework\TestCase" not found in /var/www/html/vendor/mike42/gfx-php/test/unit/IndexedRasterImageTest.php:15 Stack trace: #0 {main} thrown in /var/www/html/vendor/mike42/gfx-php/test/unit/IndexedRasterImageTest.php on line 15