1121698 - Allow to wait for observer notifications when opening new chrome windows

Status: RESOLVED DUPLICATE of bug 1504756

(Remote Protocol :: Marionette, defect, P3)

Description

[Henrik Skupin [:whimboo][⌚️UTC+1]]

Marionette is only able to return a list of open chrome windows. But it is not clear in which state such a window is. Especially when tests are opening or closing chrome windows, they have to wait until the window has e.g. been completely loaded. This can be done by listening for the appropriate observer notifications.

Currently we have this implemented in our mozmill-tests repository in the windows module:

http://hg.mozilla.org/qa/mozmill-tests/file/default/lib/windows.js

To be able to get started we need the feature to work with observers. This is being worked on in bug 1121691.

Comment 1

[Henrik Skupin [:whimboo][⌚️UTC+1]]

Seeing more and more code being asynchronous it is getting more important to get this bug fixed. Otherwise race conditions can occur.

Implementing this is actually not that easy. We would have to setup some listener Promise first, which checks for new chrome windows to get opened. Then some code has been run, which triggers the opening of the window. This is mostly a callback in Python code. Then an async execute script call has to wait for the formerly setup Promise to be fulfilled.

As an example how the server code would look like the open browser window command can be used:
https://searchfox.org/mozilla-central/rev/78cd247b5d7a08832f87d786541d3e2204842e8e/testing/marionette/browser.js#307

This would all be a lot of work to do. Seeing that the Marionette client is fading away, firefox-puppeteer would also go away.

As such it may be helpful to just have bug 1507771 fixed, which let us open the window by a chrome URL, and then wait for appropriate events and observer notifications. The only problem with this approach is, that openDialog() and passing over arguments is needed. And that is actually not ideal, because the browser itself should decide which arguments to pass over.

https://searchfox.org/mozilla-central/rev/78cd247b5d7a08832f87d786541d3e2204842e8e/browser/base/content/browser.js#2601,2618-2619

Comment 2

[Henrik Skupin [:whimboo][⌚️UTC+1]]

To be able to use promises I have to get bug 1398095 fixed first.

Comment 3

[Henrik Skupin [:whimboo][⌚️UTC+1]]

This was actually implemented via bug 1504756. Also we only care about the notifications, for that particular command. For eg clicking a link which opens a browser window, the test has to make sure to wait long enough before accessing this window.