Generating Test Cases for Composite Web Services by Parsing XML Documents and Solving Constraints

Web services are widely used nowadays for their interoperability and reusability. Since Web services only provide interface information for users and source codes are encapsulated, generating test cases for Web services in the view of users has more challenges than traditional software. We develop a constraint-solver based method to generate test cases for composite Web services. The technique first parses the related files, such as XSD (XML Schema Definition), WSDL (Web Service Description Language) and BPEL (Business Process Executing Language) scripts to obtain the constraints for variable types, in-out relations, conditions and orders. Then, by using the Z3-str solver, test cases are generated according to different testing coverage criterions. Our evaluation results indicate that our method is effective to generate test cases for Web services with high coverage and low redundancy.