Pex
Dr Peli De Halleux as many of you may know was the man who created MbUnit, when Peli joined the CLR team 2 years ago MbUnit was opensourced and here we are approaching a second milestone. Peli has a brain the size of jupiter and such a passion for testing that some day the path was going to take him back to testing tools. Last year Peli joined the FSE group at Microsoft Research, working with the researchers of MUTT (and who also wrote a paper on parameterized testing) on a project called Pex (Program EXploration).
Pex is different to the kind of parmeterized testing you will find in MbUnit, JUnit or TestNG. While you still set the input parameters, Pex then generates sets of test data across the inputs rather than using manually set ranges. Pex then monitors the test, checks code coverage, spots issues and suggests fixes. Pex is only internal at the moment but hopefully MSR will release Pex to the public soon.