On-line Test Of Composite Web Services Based On Extended Colored Petri Net

Composite web service is the key content of the Internetware. Its correct functionality directly affects its availability and user satisfaction. Its execution flow is generally described with "Business Process Execution Language"(BPEL). The practice shows that there are inconsistencies in the prevalence of composite web services described by BPEL and implementation, because of the lack of effective testing techniques, leading incorrect implementation of user transactions.With this, the paper proposes an on-line test method for composite web services, based on eXtended Colored Petri Net (XCP-Net). This method uses the XCP-Net to model BPEL-specified composite web services, and automatically generates test cases on this basis in order to detect whether the service in running conforms accurately to the BPEL specification.The paper demonstrates the following work. First, defines the model of XCP-Net, which realizes the interaction specification among users, composite service and partner service based on Colored Petri Net. Next, defines the BPEL modeling method based on XCP-Net to express complex BPEL semantics (e.g., concurrent synchronization structure and dead path clear). Finally, with the model obtained, defines the process of automatic generation of test cases, in order to implement on-line test of composite web services.Through two cases, compared against two typical test methods (BCG method and the enumeration method), the paper analyzes application performance of the proposed test method. Experiments based on cases indicate that among composite web services on-line tests, the proposed test method has two major advantages:(1) High defect detection rate, nearly90%of the implant defects can be found in both cases, which is higher than the defect discovery rate with BCG method;(2) The required number of test cases, in particular, is far less than the number of test cases required by the enumeration method. Therefore, the paper concludes that the proposed method is superior to the existing two methods, and thus might have better performance for on-line test practices of composite Web services.