Until recently, software testing has been more of an “art” than a science and a manual process. This has made unit testing time consuming and costly with unpredictable results. With the growing popularity of graphical tools, the tool vendors are starting to convert the unit testing theory into commercial tools such as I-Logix’s Statemate, ADI’s Beacon, and T-VEC. While the author has used AUTT and T-VEC, the test results available are either protected under NDA or are “toy” benchmarks whereas the below Reactis results are from “production” models being used in real applications. This paper will then concentrate on the Reactis tool from Reactive Systems that generates unit test vectors for Matlab Simulink and StateFlow models.