787116 - Marionette's printLogs should write to stderr instead of stdout

Status: RESOLVED FIXED

(Remote Protocol :: Marionette, defect)

Description

[Jonathan Griffin (:jgriffin)]

Marionette uses Python's unittest runner to run tests.  TextTestRunner outputs test results to stderr, instead of stdout, to avoid the buffering that takes places with stdout. 

Marionette's printLogs function (http://mxr.mozilla.org/mozilla-central/source/testing/marionette/client/marionette/runtests.py#65), on the other hand, just uses print, which goes to stdout.  This does get buffered, and the result is, when running a sequence of tests, that the log info does not get printed immediately after a test, as is desired, but sometime later, when the stdout buffer gets flushed.

To fix this, we should have printLogs output to MarionetteTextTestRunner.stream, which by default is sys.stderr.

Comment 1

[Hao Gao (:hao)]

If I made some changes to the code, how can I verify the result? Run the runtests.py?

Comment 2

[Jonathan Griffin (:jgriffin)]

(In reply to Hao Gao from comment #1)
> If I made some changes to the code, how can I verify the result? Run the
> runtests.py?

Yes, you can run it with desktop Firefox using a command-line like this:

python runtests.py --address localhost:2828 --binary /path/to/firefox --type browser tests/unit-tests.ini

Comment 3

[Jonathan Griffin (:jgriffin)]

I should add that in order to get a Firefox build that has Marionette enabled, you should download a debug build from e.g., http://stage.mozilla.org/pub/mozilla.org/firefox/tinderbox-builds/mozilla-central-linux-debug/ (or other, depending on your platform).

Comment 4

[Hao Gao (:hao)]

Attachment: a patch

Please review it.

Comment 5

[Jonathan Griffin (:jgriffin)]

Comment on attachment 659003 [details] [diff] [review]
a patch

Review of attachment 659003 [details] [diff] [review]:
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Looks great, thanks for contributing a patch!

Comment 6

[Jonathan Griffin (:jgriffin)]

https://hg.mozilla.org/mozilla-central/rev/00a552f644a2