We have a number of PiP tests that follow this pattern:

1. Cause the PiP player window to open
2. Do a check of some kind
3. Close the player window, and wait for the "This video is playing in Picture-in-Picture mode" message to go away in the originating video

Example: https://searchfox.org/mozilla-central/rev/cce8b90aece0f42e5025e45282de16066eeaa662/toolkit/components/pictureinpicture/tests/browser_thirdPartyIframe.js#21-46

We can / should probably factor this repeated stuff out into a helper method inside of head.js instead of repeating ourselves again and again.

It's also unclear whether those try / catch / finally blocks are really helpful.

Here are 3 instances of us doing the same things in some tests:

• https://searchfox.org/mozilla-central/rev/5d45da52f2fa423c9f4505ede5d1a5c7d48163fc/toolkit/components/pictureinpicture/tests/browser_keyboardShortcut.js#44-54
• https://searchfox.org/mozilla-central/rev/5d45da52f2fa423c9f4505ede5d1a5c7d48163fc/toolkit/components/pictureinpicture/tests/browser_showMessage.js#25-35
• https://searchfox.org/mozilla-central/rev/5d45da52f2fa423c9f4505ede5d1a5c7d48163fc/toolkit/components/pictureinpicture/tests/browser_thirdPartyIframe.js#43-55

I think we can factor these out into a helper. Our helper functions for the PiP tests go in this file:

https://searchfox.org/mozilla-central/rev/5d45da52f2fa423c9f4505ede5d1a5c7d48163fc/toolkit/components/pictureinpicture/tests/head.js

So I recommend factoring those 3 instances out into a helper function in head.js with a signature like this:

async function ensureMessageAndClosePiP(browser, videoID, pipWin) {
  //...
}

Do add a docstring above the helper function, and then update the 3 instances I listed above to use it.

You can run the tests by using:

./mach mochitest <path to test>

example:

./mach mochitest toolkit/components/pictureinpicture/tests/browser_keyboardShortcut.js

https://hg.mozilla.org/mozilla-central/rev/31d155c12756