H-Switch Cover: a new test criterion to generate test case from finite state machines

Abstract

Test cases generation based on Finite State Machines (FSMs) has been addressed for quite some time. Model-based testing has drawn attention from researchers and practitioners as one of the approaches to support software verification and validation. Several test criteria have been proposed in the literature to generate test cases based on formal methods, such as FSM. However, there is still a lot to be done on this aspect in order to clearly direct a test designer to choose a test criterion most suitable to generate test cases for a certain application domain. This work presents a new test criterion for model-based test case generation based on FSM, H-Switch Cover. H-Switch Cover relies on the traditional Switch Cover test criterion, but H-Switch Cover uses new heuristics to improve its performance, for example, adoption of rules to optimize graph balancing and traverse the graph for test cases generation. We conducted an investigation of cost and efficiency of this new test criterion by comparing it with unique input/output and distinguishing sequence. We used two embedded software products (space application software products) and mutation analysis for assessing efficiency. In general, for the case studies proposed in this paper in terms of cost (amount of events) and efficiency (mutation score), H-Switch Cover test criterion presented an average and a standard deviation better than the other two test criteria.