Development: Marionette UI tests are broken

[jrrdev]

Environment

• RPC revision: 489ddf4 (v1.0.beta13.2)
• Browser: Firefox ESR 52.5.1 / Firefox 56.0 dev edition
• Platform: Ubuntu 16.04 (32-bits)

Steps to reproduce:

1. Clone repo & set up dev environment
2. Set up an apache/php server with web server's root directory test/content/
3. Run make clean && make marionette

Problems

1. Marionette tests uses is looking for Firefox installation in .mozilla/software/firefox/default-marionette-testing/firefox instead of dev_env/browsers/firefox/default-rp-dev/firefox (the FF install path should be the same between make run and make marionette).
2. With marionette-client-2.3 and Firefox 50+, the command fails with KeyError: 'device'

• After upgrading to marionette-client-3.1:

3. With Firefox ESR 52.5.1, browser and tests are launched but a lot of tests fails (see marionette-errors-ff-52.5.1-esr.log for a sample):

SUMMARY
-------
passed: 81
failed: 105
todo: 12 (skipped: 9)

4. With Firefox 56 dev edition, all tests fails with UnknownCommandException: timeouts and ``UnknownCommandException: getLogs` (see marionette-errors-ff-56.0.log for a sample of errors)

[jrrdev]

• Problem 1 is fixed by 7aeaa10
• Problem 2 is due to this issue in marionette and fixed by 69afefa and 236d680
• Problem 4 may be caused by an incompatibility between marionette-driver-1.4 and newer version of Firefox. An upgrade may be needed.