Slope Testing for Activity Diagrams and Safety Critical Software

Formal system modeling and rigorous validation techniques have become a corner stone in the development practice for safety critical systems. It is characteristic for model-based approaches that the relationship between the model and its implementation needs to be monitored and ultimately brought to conformance. To bridge the gap between model and implementation, the current paper proposes a new methodology called slope testing where we concretize an abstract test suite covering the model to obtain a corresponding concrete test suite on the implementation. In this way, our method is able to systematically expose the potential deficiencies in the mapping between model and code. Motivated by the avionic certification standard DO-178B, we introduce slope testing in a prototypical process which is based upon UML activity diagrams and ANSI-C as the respective modeling and implementation languages. Our implementation makes use of the test case generator FShell which automatically generates the required test suites for activity diagrams and source code.