Question: I'm trying to test a simple WebForms (asp.net) based UI, and follow the MVP pattern to allow my UI to be more testable. 

As I follow the TDD methodology for backend algorithms, I find that there are some unit test refactorings that happen in the spirit of the DRY principle (Don't Repeat Yourself). As I try to apply this to the UI using Rhino Mocks to verify my interactions, I see many commonalities in the Controller tests when setting up the view or model expectations.

My question is: how far do you typically take this refactoring, if at all? I'm curious to see how other TDDer's test their MVC/MVP based UIs.

Answer: 
I would not refactor tests like standard code. Tests start to become more obscure as you refactor things into common base classes, helper methods, etc. Tests should be sufficiently clear on their own. 

DRY is not a test concern.

That said, there are many plumbing things that are commonly done, and those should be abstracted away.
I use selenium for functional testing
and I'm using JUnit to test my controllers.

I'll mock out services or resources used by the controller and test to see what URI the controller is redirecting to, etc...

The only thing I'm not really testing at this point are the views. But I have employed functional testing to compensate.