UML in action

This paper presents a novel model-based test case generation approach that automatically derives test cases from UML state machines. UML is given a two-layered formal semantics by (1) mapping UML class diagrams and state charts to Back's Action Systems, (2) by interpreting these action systems as labeled transition systems. The first semantics provides a formal framework to capture the object-oriented machinery: classes, objects, inheritance, transitions, time-outs, signals, nested and parallel regions. The second mapping represents the tester's view on the interface in terms of input and output actions. Tretman's input-output conformance relation (ioco) forms the basis of our fault models. Mutation analysis on the models is used to generate test cases. A car alarm system serves as a running example