Personally I don't think this is useful, because it won't run automatically and detect any problems.
I figured it'd be useful for interactive testing, I mean all interactive tests don't run automatically. And I don't see a better way for visual testing here.
If you want to see what it looks like or interact with it, it's trivial to make any taskdialog test not to close the dialog automatically.
That sounds hacky, I'd prefer real tests for that. Isn't that what interactvie tests are for? I mean sure, we could add a bunch of special tests that we then pause when we want to see what it looks like, but it's a lot easier to do visual checks with the creator I proposed - without having to edit any code.
Regards, Fabian Maurer