Putting Formal Specifications under the Magnifying Glass: Model-based Testing for Validation

A software development process is conceptually an ab-stract form of model transformation, starting from an end-user model of requirements, through to a system model for which code can be automatically generated. The success (or failure) of such a transformation depends substantially on obtaining a correct, well-formed initial model that cap-tures user concerns. Model-based testing automates black box testing based on the model of the system under analysis. This paper pro-poses and evaluates a novel model-based testing technique that aims to reveal specification/requirement-related errors by generating test cases from a test model and exercising them on the design model. The case study outlined in the paper shows that a separate test model not only increases the level of objectivity of the requirements, but also sup-ports the validation of the system under test through test case generation. The results obtained from the case study support the hypothesis that there may be discrepancies be-tween the formal specification of the system modeled and the problem to be solved, and that using solely formal ver-ification methods may not be sufficient to reveal these. The approach presented in this paper aims at providing means to obtain greater confidence in the design model that is used as the basis for code generation.