Visual Studio Team System (VSTS) provides all the tools necessary to build and test complex programs. Creating the right kinds of tests will take a little time and effort. Fortunately there are good resources on the Microsoft site and elsewhere to help you out. One good resource outside Microsoft is the Vertigo Software Team System blog.
A recent post entitled Team Test and the Load Test Agent discusses how you go about simulating multiple users of an application. Some good advice from this post:
While you can do some ad-hoc testing using a desktop install of Team Edition for Testers or Team Suite, if you want to simulate large numbers of users, you need to install the Load Test Agent and Load Test Controller. These are standalone components designed to run on a farm of machines. You connect to and control them with Visual Studio, via the Test, Administer Test Controllers menu.
The post also gives credit to Microsoft's Ed Glas (group manager for VSTS load testing) and his detailed post describing all the things you need to consider when setting up your test environment to do load testing. Another key point from the Vertigo post - building up this type of testing environment is not cheap. Each load agent license cost $5,089. Check out the Microsoft Purchasing Visual Studio 2005 page for all the pricing details.
MbUnit is an open source extensible unit testing framework currently maintained by Andrew Stopford. Andrew has an active blog where he frequently discusses issues related to unit testing. He also has links to other bloggers on his main page that are worth checking out. Andrew also links back to a blog post on the Vertigo site discussing TestDriven.Net and its integration with VSTS.
Paul Ferrill is a freelance technical writer. He has a BS and MS in Electrical Engineering and has been writing about computers for almost 20 years.