A Formal Specification-Based Testing Approach to Accurate Web Service Selection

Currently most web services are published without sufficient functional behavior descriptions, which makes it difficult for developers to accurately select services according to the expected functions of their target systems. In this paper, we propose a formal specification-based testing approach to accurate service selection. Requirements upon candidate services are refined into formal specifications in terms of functional scenarios. Test cases for each service operation are basically generated from its associated functional scenarios. Since the internal variables of stateful services are not allowed to be directly monitored from user-end, state transitions of these internal variables can only be checked through running inter-related operations in combination. In particular, functional scenario pairs are used as the foundation for test sequences generation so that potential combinations of interrelated operations can be tested. Conformance of candidate services with respect to users' requirements is determined based on the analysis of testing results. A running example is illustrated to demonstrate the application of this approach. We have also conducted experiments to evaluate the feasibility and the effectiveness of our conformance testing approach.