1423636 - browser_BrowserTestUtils.js fails when executed twice

Status: ASSIGNED

(Firefox :: General, defect, P3)

Description

[Tooru Fujisawa [:arai]]

bug 1416446 patch updates browser_BrowserTestUtils.js,
and I bumped into pre-existing timeout issue in the previous test.
happens only in automation.
(happens locally when I run it twice, but not yet figured out they're same issue)

https://treeherder.mozilla.org/#/jobs?repo=try&revision=ba84df02cff91b183e1bc991feff6fe4a8f196fc&selectedJob=150231677
> TEST-UNEXPECTED-FAIL | testing/mochitest/tests/browser/browser_BrowserTestUtils.js | Test timed out - [log…]
> TEST-UNEXPECTED-FAIL | testing/mochitest/tests/browser/browser_BrowserTestUtils.js | Found a tab after previous test timed out: about:blank - [log…]

looks like the test is executed only when the file is updated?

Comment 1

[Tooru Fujisawa [:arai]]

so, TV runs the test multiple times, and the failure I observed should be the same thing.

Comment 2

[Tooru Fujisawa [:arai]]

the failure reason is:
  * the test registers about: handler in the content processes, and opens the page, and then unregisters the handler
  * if the handler is registered twice with same name, even after unregistering the first one, the 2nd one cannot be opened
     and it stops

here's some observation:
  * this issue doesn't happen if I disable e10s, so this should be specific to the about handler in content process
  * this issue doesn't happen if I use different about: name every time
  * if it fails, createInstance method is called but newChannel is not called

so, quick workaround here is to use different name everytime, based on time or random value.
(and it might be nice to file a separated bug about registering same about: handler twice)

Comment 3

[Tooru Fujisawa [:arai]]

The actual consumer of the function is in 2 files:
* browser/base/content/test/general/browser_e10s_about_page_triggeringprincipal.js
* caps/tests/mochitest/browser_checkloaduri.js

browser_e10s_about_page_triggeringprincipal.js registers 2 handlers:
* about:test-about-principal-child
* about:test-about-principal-parent

about:test-about-principal-child is used also inside
* browser/base/content/test/general/file_about_parent.html

So this might require some change to the test.


caps/tests/mochitest/browser_checkloaduri.js registers 10 handlers:
* test-chrome-privs
* test-chrome-privs2
* test-unknown-linkable
* test-unknown-linkable2
* test-unknown-unlinkable
* test-unknown-unlinkable2
* test-content-unlinkable
* test-content-unlinkable2
* test-content-linkable
* test-content-linkable2

everything here is used within the file, so this won't require so much change.