csUnit is a unit testing framework for the .NET Framework. It is designed to work with any .NET compliant language. It has specifically been tested with C#, Visual Basic .NET, Managed C++, and J#. csUnit is open source and comes with a flexible license that allows cost-free inclusion in commercial closed-source products as well.csUnit follows the concepts of other unit testing frameworks in the xUnit family and has had several releases since 2002.