Fatal error: Uncaught Error: Class 'PHPUnit\Framework\TestCase' not found in /home/esecureh/public_html/magdemo/vendor/magento/module-theme/Test/Unit/Block/Adminhtml/Design/Config/Edit/SaveButtonTest.php:13 Stack trace: #0 {main} thrown in /home/esecureh/public_html/magdemo/vendor/magento/module-theme/Test/Unit/Block/Adminhtml/Design/Config/Edit/SaveButtonTest.php on line 13