Signal based functionality testing of control systems

In many industries there is a trend towards more specialized and sophisticated applications for control and supervision of the plant. Control systems in general differ from enterprise and office applications, but the demand for efficient tools and practices is very much the same. However, it seems that at least the process industry is lagging somewhat behind in adopting new tools that could facilitate development. In this paper we advocate automated functionality testing, one of the cornerstone practices in agile methods. There are indeed other areas that need attention during testing too, but functionality is perhaps the one area where automated test execution and reporting have the biggest potential. A test framework inspired by the simple yet very effective xUnit family is outlined. The underlying idea is to separate the test specification from the code by defining test case scenarios on a signal level. This approach is most advantageous for control systems, because it enables us to support a variety of platforms and languages