1238746 - Separate application-specific setup code in Marionette runner

Status: RESOLVED WONTFIX

(Remote Protocol :: Marionette, defect)

Description

[Maja Frydrychowicz :impossibus (was :maja_zf) (needinfo me)]

As part of making the Marionette runner more flexible and extensible, I'd like to decouple the runner from application-specific setup code so that, for example, Firefox-Desktop-only test suites aren't encumbered with added complexity associated with B2G emulator setup. At the same time, "platform-agnostic" tests should be able to remain as such. 

This revisits the idea that the vanilla runner should be GeckoInstance-only, say, and then additional pieces should be easy to plug in, but perhaps without relying so much on multiple inheritance.

Some context:
16:12 <mdas> it was originally to let people write tests that were platform agnostic, so the test harness would manage the platform details. but it definitely could be done a better way
16:16 <mdas> maja_zf: I think that's a side effect of using mixins, which was done because it was the easiest and unfortunately clearest way to add the functionality we wanted given unittests' weird architecture (https://bugzilla.mozilla.org/show_bug.cgi?id=925398). We essentially wanted to run the same test against B2G desktop, emulator and device without the test managing those details, but have the harness/runner deal with it
16:16 <bugbot> Bug 925398: normal, --, mozilla29, malini, RESOLVED FIXED, Refactor runtests.py to follow Mixin pattern

Comment 1

[Maja Frydrychowicz :impossibus (was :maja_zf) (needinfo me)]

Our approach has changed since fixing Bug 787203. Wontfix for now.