I have created a Mono for Android VS2010 project and added NUnit tests.
It seems Mono for Android does not support NUnit according to this post from Xamarin: https:/
For UI testing on actual devices, LessPainful announced earlier today that Calabash for Android supports it since version 0.1.0:
[...] we now support Mono for Android.
[...] Currently you can only test Release builds of your app. If you need to test Debug builds let me know.
I've not used Calabash with Mono.