Fatal error: Uncaught Error: Class "PHPUnit\Framework\TestCase" not found in /home/airtimer/public_html/vendor/magento/framework-message-queue/Test/Unit/MergedMessageProcessorTest.php:23 Stack trace: #0 {main} thrown in /home/airtimer/public_html/vendor/magento/framework-message-queue/Test/Unit/MergedMessageProcessorTest.php on line 23