We (my colleagues) have a messy 12 y.o. mature app that is GUI-based, and the current plan is to add new dialogs & other GUI in WPF, as well as replace some of the older dialogs in WPF as well. At the same time we wish to be able to test that Monster - GUI automation in a maintainable way. Some challenges:

1. The application is massive.
2. It constantly gains new features.
3. It is being changed around (bug fixes, patches).
4. It has a back end, and a layer in-between. The state of it can get out of whack if you beat it to death.

What we want is:

• Some tool that can automate testing of WPF.
• auto-discovery of what the inputs and the outputs of the dialog are. An old test should still work if you add a label that does nothing. It should fail, however, if you remove a necessary text field. It would be very nice if the test suite was easy to maintain, if it ran and did not break most of the time.
• Every new dialog should be created with testability in mind.

At this point I do not know exactly what I want, so I am marking this as a community wiki. If having to test a huge GUI-based app rings the bell (even if not in WPF), then please share your good, bad and ugly experiences here.