Mutating UML State Machine Behavior with Semantic Mutation Operators

In Model-Driven Software Development (MDSD), an application can be built using classes and their state machines as source models. The final application can be tested as any source code. In this paper, we discuss a specific approach to mutation testing in which modifications relate to different variants of behavioural features modelled by UML state machines, while testing deals with standard executions of the final application against its test cases. We have proposed several mutation operators aimed at mutating behaviour of UML state machines. The operators take into account event processing, time management, behaviour of complex states with orthogonal regions, and usage of history pseudostates. Different possible semantic interpretations are associated with each operator. The operators have been implemented in the Framework for eXecutable UML (FXU). The framework, that supports code generation from UML classes and state machines and building target C# applications, has been extended to realize mutation testing with use of multiple libraries. The semantic mutation operators have been verified in some MDSD experiments.