Today Henrik Skupin from Mozilla has announced the end of Mozmill, which RPC is currently using for UI tests. Therefore we need to move from Mozmill to Marionette.

So this issue consists of the following steps:

• Introduce Marionette, i.e. adapt RPC's development environment so that Marionette can be used.
• Migrate existing Mozmill tests to Marionette.

More info about Marionette:

• https://developer.mozilla.org/en-US/docs/Mozilla/QA/Marionette
• [Project] migration from Mozmill to Marionette: https://wiki.mozilla.org/Auto-tools/Projects/m21s
• [Github] Firefox UI tests repo: https://github.com/mozilla/firefox-ui-tests
• [read the docs] Marionette Python Client: https://marionette-client.readthedocs.org/en/latest/
• [read the docs] Firefox Puppeteer: https://firefox-puppeteer.readthedocs.org/en/latest/
• [python] „unittest“ – unit testing framework: https://docs.python.org/2/library/unittest.html