tl;dr - You can now set prefs and install extensions across multiple harnesses by modifying the relevant profile under testing/profiles.
If you previously would have set a pref in: testing/profiles/prefs_general.js, Use this instead: testing/profiles/unittest/user.js # Overview I'm currently in the process of consolidating prefs and extensions across all our test harnesses into a single shared location (testing/profiles <https://searchfox.org/mozilla-central/source/testing/profiles>). If you navigate there you'll find several different "profile-like" directories. Each profile directory has a user.js file for setting prefs, and an extensions dir for dropping in extensions. I call these directories "profile-like" because they only currently support prefs and extensions. Don't expect to be able to add other profile-related files (though if there's a need, support for other kinds of profile data can be implemented). You'll also find a 'profiles.json' file, and a 'profile' utility script. The JSON file is used to map test suites to a list of profile directories to apply. For example, mochitest uses the 'common' and 'unittest' profiles in that order. Prefs from the latter profiles will overwrite prefs from the earlier ones. This means you can either set prefs for a single harness (e.g by adding them to the latter profile), or set prefs across all harnesses at the same time (e.g by adding them to the 'common' profile). Same goes for extensions. Because prefs are split across multiple directories, and those directories can overwrite one another, the 'profile' utility script can help you view and compare the contents of a profile. For example: $ cd testing/profiles $ ./profile show mochitest # dumps all prefs that mochitest will use You can also diff profiles or sort preference files alphabetically: $ ./profile diff mochitest talos $ ./profile sort mochitest In the future, I may add a command to automatically set preferences in a given list of suites. # Motivations One great use case is testing the impact prefs and extensions have on our performance (and unittests). Simply drop an extension into testing/profiles/common/extensions and push to try. It will be installed in all of our harnesses (that use this system), including Talos. Another reason for this change is that it provides more visibility into which prefs are set in which harnesses. We can now diff the prefs set in various suites to try and reason about whether those differences are intentional or omissions. Lastly, this will make it easier to set prefs. No more hunting around the tree looking for preference files. This will help prevent cases where a pref was accidentally omitted from a test harness. # Further Work I'm in the middle of migrating harnesses over to this new system. Notably, reftest and xpcshell have not yet been converted, though hopefully these will be done soon. There is a long tail of smaller harnesses that I might not have time to get around to however. For current support, just look here: https://searchfox.org/mozilla-central/source/testing/profiles/profiles.json Here's the relevant bug tree: https://bugzilla.mozilla.org/showdependencytree.cgi?id=1451159&hide_resolved=0 Let me know if you have any questions or concerns, Andrew _______________________________________________ dev-platform mailing list dev-platform@lists.mozilla.org https://lists.mozilla.org/listinfo/dev-platform
