Kent Beck has released JUnitMax. "JUnit Max is an Eclipse plug-in that helps programmers stay focused on coding by running tests intelligently and reporting results unobtrusively. Every time you save a Java file, Max will run your tests and report errors like compile errors. In addition, Max runs the tests most likely to fail first, so you only have to pay close attention to test results for a second (literally) before getting back to coding, even if you have a long-running test suite." The licensing model is one I haven't seen before: $2/month. "If you stop paying, please stop using it."