Test Case Generation and Prioritization for Semantic Based Web Services Using Orthogonal Array Testing Technique

Web Services (WS) are the basic building blocks for every e-business applications. They provide efficient reusability mechanism, thereby reducing the development time and cost. Web services can be identified by Uniform Resource Identifier (URI). The interfaces and bindings of Web Services can be discovered, defined and described as XML artifacts according to Web Service Description Language (WSDL). WSDL can be used to describe web service operations including input, output and exceptions. It cannot identify pre and post conditions of web services. But Semantic WSDL (WSDL-S) identifies the pre and post conditions of web services to generate optimal number of test cases. This paper presents an approach for generating web service test cases using WSDL-S and Object Constraint Language (OCL), while the test case generation technique is Orthogonal Array Testing (OAT). We have generated WSDL of web service to be tested using NetBeans IDE and converted into WSDL-S by giving OCL references, where pre and post conditions are defined. Test data, using OAT, with different factors, levels and strengths are generated and documented in XML based test files called Web Service Test Specifications (WSTS) and executed. Test cases are prioritized based on different criteria like statement coverage, condition coverage, execution time and fault rate. We have conducted testing on various web service applications and the results have shown that the test case prioritization based on fault rate is effective for determining the faults earlier and it is proved by the metric Average Percent of Fault Detection (APFD).