Scenario-Based Design and Validation of REST Web Service Compositions.

We present an approach to design and validate RESTful composite web services based on user scenarios. We use the Unified Modeling Language (UML) to specify the requirements, behavior and published resources of each web service. In our approach, a service can invoke other services and exhibit complex and timed behavior while still complying with the REST architectural style. We specify user scenarios via UML Sequence Diagrams. The service specifications are transformed into UPPAAL timed automata for verification and test generation. The service requirements are propagated to the UPPAAL timed automata during the transformation. Their reachability is verified in UPPAAL and they are used for computing coverage level during test generation. We validate our approach with a case study of a holiday booking web service.