Two days ago we successfully finished the first Developer Days event on Cyprus. It was a great event, where we discussed lots of technologies (24 I think was the total number) and as you can imagine there were lots of questions from the audience as well …
One of them was related to the integration of NUnit tests into the TFS project in a sense how to approach it and if it is even possible to do it. Actually when TFS was first coming out with VS 2005 there was a converter for NUnit tests into VS Tests posted on gotdotnet, but that project was later abandoned. My guess is that NUnit changed the complexity of their tests in such a way that they cannot be converted to VSTS tests automatically.
So what you can do today is basically continue to use NUnit if all of your tests are already implemented and you would like to avoid manual work of converting them to VSTS tests (you can do that by proper substitution of classes in your code but it is quite a tedious job). As a result NUnit can be integrated into VS TFS in 2 ways:
I guess these options come in handy for all of you with lots of NUnit tests already defined. But be aware that with VSTS 2010 MS will provide lots of extra functionality for testers, so you might consider even creating your tests in VS Unit Testing environment from scratch as well. Happy testing!