Update the Functional Testing Framework
Two types of updates are available.
Use this type of update if the version of the Functional Testing Framework in <magento2>/dev/tests/functional/composer.json and last version in <magento2>/dev/tests/functional/vendor/magento/mtf/CHANGELOG.md are different. For example, when you updated Magento.
Use this type of update if you want to update dependent software from composer.json, or changed composer.json dependencies.
Install a new version of the Functional Testing Framework
Step 1. To avoid conflicts with the previous version, remove directory <magento2_root_dir>/dev/tests/functional/generate.
Step 2. Remove file <magento2_root_dir>/dev/tests/functional/composer.lock.
Why: Composer reads dependencies from composer.lock instead of reading composer.json. File composer.lock currently is not maintained.
Step 3. Perform and check installation.
Update components from dependencies in composer.json
Enter in terminal:
cd <magento2_root_dir>/dev/tests/functional/
composer update