Fatal error: Uncaught Error: Class 'PHPUnit\Framework\TestCase' not found in /home/geofieldwa/www/concrete/vendor/ssddanbrown/htmldiff/tests/HtmlDiffTest.php:6 Stack trace: #0 {main} thrown in /home/geofieldwa/www/concrete/vendor/ssddanbrown/htmldiff/tests/HtmlDiffTest.php on line 6