Characterization Tests & Legacy Modernization

In the book "Working Effectively with Legacy Code", Michael Feathers discusses "characterization tests" which are unit tests written explicitly for the purpose of capturing the current functionality of the code and record how it operates.

Agitar now supplies an Eclipse plug-in which sends the code to Agitar's servers where dozens of tests per class are generated and shipped back to your desk-top. These tests are designed to pass and as the legacy code is modified, augmented, or re-factored some or all of these tests will fail due to changes that have broken the functionality of the code.

Check out the beta version @ http://www.junitfactory.com/.