Has anyone got a TDD-ish methodology for designing complex WPF xaml components (i.e., ControlTemplates, Custom Controls with dependency properties)?
Is eyeballing the UI the closest you can come to asserting your code is correct? How about incremental development; any aids to dividing up the logic incrementally?
If there isn't any methodologies for doing this now, do you think there will be as the platform continues to mature and gain adoption?
To be more focused and avoid introductions to TDD, please consider the topic for an audience that is fairly seasoned in applying TDD to a traditional code base (including MVVM).
The silverlight toolkit provides all the unit test and the source code... on http://silverlight.codeplex.com/
For UI testing I think some folks use the Silverlight Accessibility api http://msdn.microsoft.com/en-us/library/cc707824(VS.95).aspx ....
And there are also tools for UI testing, too
MSDN Magazine article on UI-Testing http://msdn.microsoft.com/en-us/magazine/dd483216.aspx
Testing using WPF UI automation Link
It is surely not an easy and obvious topic and it always depends on the business case...
And for TDD in general look at this book: The art of Unit Testing...