Model Based Testing with Labelled Transition Systems

Model based testing is one of the promising technologies to meet the challenges imposed on software testing. In model based testing an implementation under test is tested for compliance with a model that describes the required behaviour of the implementation. This tutorial chapter describes a model based testing theory where models are expressed as labelled transition systems, and compliance is defined with the ‘ioco’ implementation relation. The ioco-testing theory, on the one hand, provides a sound and well-defined foundation for labelled transition system testing, having its roots in the theoretical area of testing equivalences and refusal testing. On the other hand, it has proved to be a practical basis for several model based test generation tools and applications. Definitions, underlying assumptions, an algorithm, properties, and several examples of the ioco-testing theory are discussed, involving specifications, implementations, tests, the ioco implementation relation and some of its variants, a test generation algorithm, and the soundness and exhaustiveness of this algorithm.