Do you know any techniques and tools for testing Windows 8 applications?

Have any of you ever done automated testing of Windows 8 Tablet applications? Do you have any recommendations for automation tools to help with the process? Do you have any recommended approaches to doing automation with this platform? Anything I can read or look at to help me with this process?

We had talks about Selenium Webdriver and Protractor. I was going to look at Appium as well to see if that can help.

Thanks so much for your feedback!