Fatal error: Uncaught Error: Class "PHPUnit\Framework\TestCase" not found in /var/www/html/upload/PhpSpreadsheet-master/vendor/squizlabs/php_codesniffer/tests/Core/AbstractMethodUnitTest.php:19 Stack trace: #0 {main} thrown in /var/www/html/upload/PhpSpreadsheet-master/vendor/squizlabs/php_codesniffer/tests/Core/AbstractMethodUnitTest.php on line 19