While at TechEd Europe in November 2009 I had a chance to catch up with the two lead developers of the Pex team
Peli de Halleux
Pex enables white box testing. It looks at your code, finds all the branches and determines which inputs will result in those branches being executed. Pex attempts to exercise every reachable statement in your code.
It works with Visual Studio 2008 and Visual Studio 2010 Beta 2 and is restricted to .NET programs. It is
available on devlabs
One of the features we discuss is Moles. Moles allows you to
isolate tests from the environment - to replace any .NET method with your own delegate. This makes it easy to test code which has hard dependencies on databases, web services etc.
I also did a
short blog post
outlining the stubs and moles capabilitie of Pex.
Pex is an incubation project - hence feedback from developers is hugely important.