1551283 - mochitest should attempt to close open tabs when failing to obtain focus

Status: NEW

(Testing :: Mochitest, enhancement, P3)

Description

[Bob Clary [:bc] (inactive)]

When the browser is unable to focus the main test window, mochitest will issue the following error:

INFO Error: Unable to restore focus, expect failures and timeouts.

I have found during inspection of test runs that this condition can occur if a tab has been left open and selected.

We can help the situation when we hit this condition if we:

1. select the main tab
2. close all other tabs
3. issue a test failure on the currently running test.

#1 and #2 will help prevent the test run from stalling or causing failures in subsequent tests while #3 would help in identifying and fixing problematic tests.

Comment 1

[Bob Clary [:bc] (inactive)]

arai: I was wondering if you could help guide me on how to approach this?

Comment 2

[Tooru Fujisawa [:arai]]

1. select the main tab
2. close all other tabs

afaik, TestRunner.js is running in tab content, and has no direct access to tabs.
so we should add SpecialPowers API [1] for those steps I think.
(there may be other ways that I'm not aware of tho, I don't know much about mochitest env)

3. issue a test failure on the currently running test.

TestRunner._makeIframe [2] fails on the other test than the problematic test, so, it should remember the previous test's URL to report,
that I think could be stored in the global variable.

Also, given the problematic test doesn't finish properly, the subsequent tests may run with non-clean environment (prefs etc), so the warning about the failure should still be shown.

let me know if there's anything unclear.

[1] https://searchfox.org/mozilla-central/source/testing/specialpowers/content/specialpowersAPI.js
[2] https://searchfox.org/mozilla-central/rev/cc280c4be94ff8cf64a27cc9b3d6831ffa49fa45/testing/mochitest/tests/SimpleTest/TestRunner.js#304

Comment 3

[Bob Clary [:bc] (inactive)]

I'm not likely to look at this any time soon.