Advances in Automated Model-Based System Testing of Software Applications with a GUI Front-End

Despite the ubiquity of software applications that employ a graphical-user interface (GUI) front-end, functional system testing of these applications has remained, until recently, an understudied research area. During “GUI testing,” test cases, modeled as sequences of user input events, are created and executed on the software by exercising the GUI's widgets. Because each possible sequence of user events may potentially be a test case and today's GUIs offer enormous flexibility to end-users, in principle, GUI testing requires a prohibitively large number of test cases. Any practical test-case generation technique must sample the vast GUI input space. Existing techniques are largely manual, and hence extremely resource intensive. Several new automated model-based techniques have been developed in the past decade. All these techniques develop, either manually or automatically, a model of the GUI and employ it to generate test cases. This chapter presents the first detailed taxonomy of these techniques. A small GUI application is used as a running example to demonstrate each technique and illustrate its relative strengths and weaknesses.