Fatal error: Uncaught Error: Class "PHPUnit\Framework\TestCase" not found in /home/amzgreatvaluesto/public_html/amz_sp/vendor/jlevers/selling-partner-api/test/RequestSignerTest.php:15 Stack trace: #0 {main} thrown in /home/amzgreatvaluesto/public_html/amz_sp/vendor/jlevers/selling-partner-api/test/RequestSignerTest.php on line 15