I am using Magento 2.3.4 and MFTF 2.6.3. I have setup the MFTF by

  • setting environment credentials in dev/test/acceptance/.env
  • running vendor/bin/mftf build:project
  • running vendor/bin/mftf generate:tests

When I execute vendor/bin mftf run:test AdminLoginTest I am getting the following error:

PHP Fatal error: Uncaught Error: Class 'Symfony\Component\HttpFoundation\File\MimeType\MimeTypeGuesser' not found in root/vendor/magento/magento2-functional-testing-framework/src/Magento/FunctionalTestingFramework/Allure/Event/AddUniqueAttachmentEvent.php:76
Stack trace:
/root/vendor/magento/magento2-functional-testing-framework/src/Magento/FunctionalTestingFramework/Allure/Event/AddUniqueAttachmentEvent.php(43): Magento\FunctionalTestingFramework\Allure\Event\AddUniqueAttachmentEvent-guessFileMimeType('/tmp/allure-att...')
/root/html/vendor/allure-framework/allure-php-api/src/Yandex/Allure/Adapter/Event/AddAttachmentEvent.php(35): Magento\FunctionalTestingFramework\Allure\Event\AddUniqueAttachmentEvent-getAttachmentFileName(Object(PHPUnit\Framework\ExceptionWrapper), NULL)
/root/vendor/allure-framework/allure-php-api/src/Yandex/Allure/Adapter/Allure.php(116): Yandex\Allure\Adapter\Event\AddAttachmentEvent->process(Object(Ya in
  • What is your question? What did you execute? Did you install Magento using composer?
    – Daniel
    May 12, 2020 at 9:58
  • 1
    Hi Daniel, I have install magento using composer, and created user credentials for backend. Configured details in MFTF .env File inside dev/test/acceptance folder. I have run vendor/bin/mftf build:project and generate:tests commands. when i execute vendor/bin mftf run:test AdminLoginTest i'm getting the above error in console: PHP Fatal error: Uncaught Error: Class 'Symfony\Component\HttpFoundation\File\MimeType\MimeTypeGuesser'
    – Dhruva's
    May 12, 2020 at 10:49

2 Answers 2


The problem lies in the missing requirement of symfony/http-foundation. See https://github.com/magento/magento2-functional-testing-framework/issues/758 for more details.

Updating the MFTF to ^2.6.4 should solve your issue since they added symfony/http-foundation to the composer.json.

If you're running Magento <2.3.4 and an update is not possible you can downgrade to version ~2.4.5.

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