Testing UML statecharts

Statechart diagrams provide a graphical notation to model dynamic aspects of system behaviour within the Unified Modelling Language (UML). In this paper we present a formal framework for notions related to testing and model based test generation for a behavioural subset of UML Statecharts (UMLSCs). This framework builds, on one hand, upon formal testing and conformance theory that has originally been developed in the context of process algebras and Labeled Transition Systems (LTSs), and, on the other hand, upon previous work of ours on formal semantics for UMLSCs. The paper covers the development of proper extensional testing preorders and equivalence for UMLSCs. An algorithm for testing equivalence verification is presented which is based on an intensional characterization of the testing relations. Testing equivalence verification is reduced to bisimulation equivalence verification. The paper also addresses the issue of conformance testing and presents a formal conformance relation together with a test case generation algorithm which is proved sound and exhaustive w.r.t. the conformance relation. We show results also on the formal relationship of the testing relations with the conformance one. The comprehensive and uniform approach presented in this paper sets the theoretical basis for UMLSCs testing frameworks and makes them available for practitioners in industry where the UML has become a de facto standard, in particular there where it is used for the development of compex concurrent systems.