This test seems to be testing useless behaviour: a right Cmd click opening a context menu. Reading bug 1421213, where the test was introduced, it looks like it's the result of a miscommunication in the review process where the reviewer wanted to make sure that Ctrl+clicking on Mac also opened the context menu. The window object here also appears to be the hidden window. Which is all to say: the test is busted as-is. Even without native context menus, you can see it opens context menus over context menus, far away from the node its supposed to be clicking on. It seems to pass now sort of accidentally, with a subsequent test accidentally cleaning it up.

I'm going to remove the right Cmd+click case, and clean up the test.

The openContextMenu() helper does the same thing this test does now: dispatches a MouseEvent to a specified node. Using it allows us to clean up the test considerably.

https://hg.mozilla.org/mozilla-central/rev/30af39798ccf

https://hg.mozilla.org/releases/mozilla-beta/rev/d54e3ff08571