MbUnit is a unit testing framework for the .NET Framework that takes in and goes beyond xUnit pattern testing. MbUnit is a part of the Gallio bundle. There are two current versions of MbUnit, v2 and v3. MbUnit v3 is the current version which is based on the Gallio Test Automation Platform. It provides a suite of testing features, native support for .Net 2.0 and .Net 3.5, better documentation, and cross-platform compatibility with Mono. MbUnit v2 is the older version and is actively maintained. It is possible to use both MbUnit v2 and v3 at the same time with the Gallio test runners.