NUnit

Similar to NANT, NUnit has its roots in the Java world as reimplementation of the Apache JUnit Java Unit Testing package. Don't let that put you off; it was excellent for Java and version 2.0 of NUnit recently released is a ground-up reimplementation which offers support for pretty much everything you might want during unit testing. A Visual Studio add-in is also available.

Link

http://sourceforge.net/projects/nunit/