Achieving communication coverage in testing

Abstract

This paper considers the problem of testing the communication between components of a timed distributed software system. We assume that communication is specified using timed interface automata and use computational tree logic (CTL) to define coverage criteria that refer to send- and receive-statements and communication paths. Given such a state-based specification of a distributed system and a concrete coverage goal, a model checker is used in order to determine the coverage provided by a finite set of test-cases, expressed using sequence diagrams. If parts of the specification remain uncovered then a goal is derived so that the model checker can be used to generate test cases that increase the coverage provided by the test suite. A major benefit of the presented approach is the generation of a potentially minimal set of test cases with the confidence that every interaction between components is executed during testing. A potential additional benefit of this approach is that it provides a visual description of the state based testing of distributed systems, which may be beneficial in other contexts such as education and program comprehension. The complexity of our approach strongly depends on the input model, the testing goal, and the model checking algorithm, which is implemented in the used tool. While a particular model checker, UPPAAL, was used, it should be relatively straightforward to adapt the approach for use with other CTL based model checkers.