.NETUnit
An implementation of Kent Beck's famous XUnit testing framework designed specifically for unit testing components written for the .NET platform.

Aut
A project intending to extend and advance unit testing methodologies with the intention of moving unit testing into a more widely accepted discipline, possibly integrated with future development platforms.

ClrUnit
A .NET unit testing framework inspired by JUnit. Features full integration with Visual Studio .NET 2003.

csUnit
csUnit is your unit testing tool for the Microsoft .NET Framework. You can use it with all .NET languages including C#, Visual Basic .NET, J#, and managed C++

dotunit
dotunit is a port of JUnit to the Microsoft .net platform. This testing framework allows for automated unit and functional tests which are vital for refactoring and regression testing.

MbUnit
MbUnit is an evolutive Unit Test Framework for .Net. It provides new fixtures as well as the framework to create new ones. MbUnit is based QuickGraph, a directed graph library for C#.

Nester
Nester is a tool for mutation analysis of your source code in order to assess the adequacy of your tests. It involves modification of programs to see if existing tests can distinguish the original program from the modified program. Basically Nester is a .NET port of Jester slightly adjusted for C#.

NMock
NMock is a dynamic mock-object library for .NET. Its purpose is to provide a clean API for rapidly creating mock implementations of custom objects and verifying that objects interact with them correctly from unit tests.

NUnit
NUnit is a unit-testing framework for all .Net languages. Initially ported from JUnit, the current version, 2.2 is the fourth major release of this xUnit based unit testing tool for Microsoft .NET. It is written entirely in C# and has been completely redesigned to take advantage of many .NET language features, for example custom attributes and other reflection related capabilities. NUnit brings xUnit to all .NET languages.

NUnit2Report
The goal of the NUnit2Report task is to merge the individual XML files generated by the NUnit2 task and apply a stylesheet on the resulting merged document to provide a browsable report of the testcases results.