For .NET developers a very usefull and free framework for unit testing is NUnit, that is a .NET implementation of the popular JUnit for Java.

I am using this for unit testing zigGIS, the Open Source ArcGis Desktop connector for PostGIS in which I am currently involved.

I will show you in this post how easy and powerfull is to create, run and debug unit test for a .NET library or application.

After installing NUnit, you can add a reference to it in your VS solution. After doing so you are ready to implement one or more classes (fixtures) for performing unit tests.
Read more