csUnit : Key to Unit testing

Inspired by JUnit, csUnit brings the power of unit testing to the .NET framework. csUnit is your key to unit testing and test-driven development using .NET languages such as C#, Visual Basic .NET, Visual J#, or Managed C++.

Founded in 2001, csUnit has improved over many releases, features a rich set of assertions, support for multiple categories, and includes a command line, a native front-end, and an add-in for Visual Studio.

Reference: http://www.csunit.org/