Code review comment for lp:~stolowski/unity-scope-click/two-columns-layout

> I'm a bit worried that we have multiple new methods being added here, and some
> changes to some previews, but there are no changes to the tests. Can we get
> some tests added for the new methods, and tests that ensure the correct
> version of the pushPackagePreviewWidgets() method is called for the different
> preview types, perhaps?

Ok, I added some tests, mostly for the new pushPackagePreviewWidgets to confirm it does the right thing, plus also added simple checks for calls to register_layout in other two existing tests.

The best test would be to just set call expectations on register_layout() and push() of the reply objects, but that's not possible without spendings tons of time on enhancing current tests. The problem is it's not currently easily possible with InstalledPreview test, because of the entire "run with qt" story in InstalledPreview::run (multiple calls to run various Qt tasks there).