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