Automatic test set generation for function block based systems using model checking

Many nuclear instrumentation and control (I&C) systems are designed using a function block diagram description of the system. Strict requirements pertain to the verification of these systems. Different verification techniques, including structure-based testing, are demanded by standards and the regulators. Unfortunately, the traditional structure-based test techniques intended for software code are not directly applicable to function block diagrams. However, coverage criteria for function block diagrams have recently been developed. In this work we have used these coverage criteria and developed a technique for generating structure-based test sets for function block based designs. The test set is automatically generated but the technique requires that a model checking model of the system is available. The technique utilises model checking to determine the concrete test cases. We have also described how tests can be generated so that multiple test requirements can be fulfilled at once, thus decreasing the number of generated test cases. We have implemented our approach as a proof-of-concept tool, and demonstrated the technique on a case study system.