Fatal error: Uncaught Error: Class 'Yii' not found in /var/www/html/forms_dir/vendor/yiisoft/yii2-swiftmailer/tests/MailerTest.php:8 Stack trace: #0 {main} thrown in /var/www/html/forms_dir/vendor/yiisoft/yii2-swiftmailer/tests/MailerTest.php on line 8