Fatal error: Uncaught Error: Class "PHPUnit\Framework\TestCase" not found in /var/www/html/phpkobo/research/php-downloaded-apps/phpmailer-5-2-16/PHPMailer-5.2.16/vendor/symfony/validator/Tests/Mapping/PropertyMetadataTest.php:18 Stack trace: #0 {main} thrown in /var/www/html/phpkobo/research/php-downloaded-apps/phpmailer-5-2-16/PHPMailer-5.2.16/vendor/symfony/validator/Tests/Mapping/PropertyMetadataTest.php on line 18