Test Case Generation For Web Service Based On The Mutation For OWL-S Documents

Web Service is a mainstream implementation technique of SOA (Service-Oriented Architecture). In the processes of its publication, discovery and composition, the service description document plays a key role. WSDL and OWL-S are the main Web service description languages. The service description document is the primary source of the test information. Compared with the WSDL document, the OWL-S document contains more detailed information about Web Service, so it suits to be the source of the test information.Mutation testing is an error based test method. The error versions of the program are simulated by mutants generation, and Mutation Score can be used to evaluate the test case set. Mutation testing is widely used in different situations, including the layer of specification testing. There are researches using this technique for the optimization of test set to Web service. To kill mutants, the generated test cases will have high capability of error detection.This paper proposes a test case generation framework based on the mutation of Web services OWL-S documents. The framework has a strong applicability and is a scalable method with high error coverage. The main work includes analyzing satisfaction (reachable and necessary) conditions of test cases, and designing test case from weak mutation strategy. They are listed as follows:(1) Considering the traditional mutation operators and the features of Service Model part in the OWL-S documents,16mutation operators are proposed, and the necessary conditions are summarized at the same time.(2) The FG4CWS (Flow Graph for Composite Web Service) model is proposed to express the Web Service, which contains the control flow information and data flow information in the OWL-S document. According to the position of mutate statement and the reachability condition of the node in the FG4CWS, the reachability condition can be summarized. And using the data flow information contained, the two constraint conditions will be transformed to restrictions over Web service input.(3)The Web service:Find-cheaper-book is used as an example. The FG4CWS is constructed, and13mutation operators are used on the OWL-S document. For each mutant generated, the constraints for the test cases should satisfy are summarized. By the solutions of constrained conditions, the final test cases can be obtained. By comparing the different numbers of the test cases needed to satisfy the required Mutation Scores, our method can generate less test cases to achieve better test effect. The necessary of Selective Mutation and the effect of13mutation operators used in this Web Service are also analyzed in this example.