Requirements-Driven Verification of Web Services

We propose a requirements-driven approach to the design and verification of Web services. The proposed methodology starts from a requirements model, which defines a business domain at a “strategic” level, describing the participating actors, their mutual dependencies, goals, require- ments, and expectations. This business requirements model is then refined into a business process model. In this refinement, definitions of the processes carried out by the actors of the domain are added to the model in the form of BPEL4WS code. We show how to exploit model checking tech- niques for the verification of the specification, both at the requirements and at the process level. At the requirements level, model checking is used to validate the specification against a set of queries specified by the designer; at the process level, it is used to verify if the BPEL4WS processes satisfy the constraints described in the requirements model.