Extending WSDL to facilitate Web services testing

Web services might be the most popular and powerful software development technology in today's software world. Yet it brings software developers and testers a lot of challenges also. This is mainly caused by the insufficient information provided by the WSDL file of a Web service. From the WSDL file, we can not get the information useful for testing, such as dependence information. To solve this problem, we proposed and practiced to extend the WSDL to support this kind of information description. In this paper, four kinds of extension are considered: input-output dependency, invocation sequence, hierarchical functional description and concurrent sequence specifications. Also their advantages are discussed.