Regression testing Web services-based applications

Web applications can be composed of heterogeneous self-contained web services. Such applications are usually modified to fix errors or to enhance their functionality. After modifications, regression testing is essential to ensure that modifications do not lead to adverse effects. In this paper, we present a safe regression testing algorithm that selects an adequate number of non-redundant test sequences aiming to find modification-related errors. In our technique, a web application and the behavior of its composed components are specified by a two-level abstract model represented as a Timed Labeled Transition System. Our algorithm selects every test sequence that corresponds to a different behavior in the modified system. We discuss three situations for applying this algorithm: (1) connecting to a newly established web service that fulfills a composed web service, (2) adding or removing an operation in any of the composed web services, (3) modifying the specification of the web application. Moreover, modifications handled by the algorithm are classified into three classes: (a) adding an operation, (b) deleting an operation, (c) fixing a condition or an action.