helper.js, I'm looking at you. Also waitForValue() - thought you could hide didn't you.
I think we do this pretty well today with head.js files... Though I suppose even those could use some sharing across tools.
can't we use add-ons for this?
This is how we do it currently: https://hg.mozilla.org/mozilla-central/file/c13b6926e6eb/browser/devtools/commandline/test/head.js#l13 It's not great, but it works. Honestly, I'm not sure this is valuable to track. Maybe in the future we find a bigger need for sharing test modules, but right now this somewhat hacky solution works, and making it cleaner wouldn't be on any priority list.