WrapThat is a library for wrapping C# .net System namespace classes. The purpose is to be able to unit test code that depends on these system classes, by wrapping them so that their new interfaces can be mocked using standard mocking tools.
See this blog post for details http://hermit.no/wrapthat-system-wrappers-for-system-io-to-simplify-unit-testing/
The library is available on Nuget here: https://www.nuget.org/packages/WrapThat.System