Existing downloads tests in http://mxr.mozilla.org/mozilla-central/source/browser/metro/base/tests/mochitest/browser_downloads.js are being modified in bug 883951 to include "TODOs" so that the tests are applicable for the new download flow. Some more testing would be nice. This includes testing for: * State variables having correct/expected values in the Downloads object in downloads.js * The correct notifications are showing up at the correct time. This includes checks like "notificationBox.getNotificationWithValue("download-progress")" returns a progress notification when there are downloads in progress (Similar checks can be done for "download-complete", "download-failed" etc).

not that we shouldn't work on them *now*, but I'd ship the preview if the tests were not finished.

The lack of tests is making it hard to progress on preview downloads features/bugs. I want to use this bug to sketch out some mochitests that assert the basic behavior we want to support and help us know when a given feature is done.

Not currently working on this. I have exploratory/WIP patches, needinfo me if you pick this up