Re: Stability testing of PRs

Hi James,

These CI tests are failing for this PR: and I don't know why.

That PR is very simple - it should improve the stability of the test in
question. But anyway, it's an encrypted-media test and I don't believe
either Firefox or Chrome have integrated those with their own tests systems

Any advice on why the job is failing much appreciated. We're blocked from
merging the PR, which fixes a broken test.


On Thu, Oct 20, 2016 at 6:30 AM, James Graham <>

> On 17/10/16 15:42, James Graham wrote:
>> Unstable tests are one of the biggest problems with running
>> web-platform-tests — or any tests — on browser CI infrastructure, and in
>> particular I have found that unreliable web-platform-tests are one of
>> the biggest problems when importing tests into the Mozilla CI system,
>> often forcing me to perform multiple, slow, end-to-end runs, and disable
>> tests, before landing the change.
>> In order to alleviate this problem, I implemented a travis job that
>> checks submitted tests produce stable results in 10 runs of the latest
>> public version of Firefox / Chrome. The code is in PR/3975 [1]. This PR
>> is pending a release of the Firefox remote control library (marionette)
>> and code review, but after those conditions are met I intend to turn it
>> on as soon as possible. I would also like to add Edge and Safari; Edge
>> seems possible using Appveyor, Safari may be possible on Travis. However
>> given the relative difficulty of testing those browsers locally I don't
>> intend to work on this immediately.
>> I expect there will be some cases where this job fails due to legitimate
>> browser bugs causing instability. In that case I think that a comment
>> indicating that the test author has investigated the issue and concluded
>> that it must be a browser bug should be enough for an admin to merge in
>> this case.
> This has now landed.

Received on Friday, 21 October 2016 00:04:10 UTC