Model-Checking-Based Automated Test Case Generation for Z Formal Specification of an Urban Railway Interlocking System

Abstract

Testing safety-critical software systems like urban railway interlocking systems is crucial since a software crash may lead to a terrible loss of assets and human life. A key problem in testing safety-critical software systems is the generation of a test suite that can detect feasible faults. The reliability of safety-critical systems is based on the precise functional requirements specification. These functional requirements are made precise by formal specification languages like Z. Formal specifications have less probability of producing an implementation that does not meet the client's requirements. To confirm that the implementation that is to be deployed in the real world, meets the client's requirements, it is essential to test it. This research article exhibits a model-checking-based method to produce a test suite of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathbf{Z}$</tex> formal specifications using the ProZ model-checking tool. The model-checking-based method uses a breadth-first search method to produce test cases. Finally, as a case study, we applied this methodology to the formal model of an urban railway interlocking system to generate test cases.