Harnessing Automated Test Case Generators for GUI Testing in Industry

Modern graphical user interfaces (GUIs) are highly dynamic and support multi-touch interactions and screen gestures besides conventional inputs via mouse and keyboard. Hence, the flexibility of modern GUIs enables countless usage scenarios and combinations including all kind of interactions. From the viewpoint of testing, this flexibility results in a combinatorial explosion of possible interaction sequences. It dramatically raises the required time and effort involved in GUI testing, which brings manual exploration as well as conventional regression testing approaches to its limits. Automated test generation (ATG) has been proposed as a solution to reduce the effort for manually designing test cases and to speed-up test execution cycles. In this paper we describe how we successfully harnessed a state-of-the-art ATG tool (Randoop) developed for code-based API testing to generate GUI test cases. The key is an adapter that transforms API calls to GUI events. The approach is the result of a research transfer project with the goal to apply ATG for testing of human machine interfaces used to control industrial machinery. In this project the ATG tool was used to generate unit test cases for custom GUI controls and system tests for exploring navigation scenarios. It helped to increase the test coverage and was able reveal new defects in the implementation of the GUI controls as well as in the GUI application.