Visual Web Test Repair

Web tests are prone to break frequently as the application under test evolves, causing much maintenance effort in practice. To detect the root causes of a test breakage, developers typically inspect the tests interactions with the application through the GUI. Existing automated test repair techniques focus instead on the code and entirely ignore visual aspects of the application. We propose a test repair technique that is informed by a visual analysis of the application. Our approach captures relevant visual information from tests execution and analyzes them through a fast image processing pipeline to visually validate test cases as they re-executed for regression purposes. Then, it reports the occurrences of breakages and potential fixes to the testers. Our approach is also equipped with a local crawling mechanism to handle non-trivial breakage scenarios such as the ones that require to repair the tests workflow. We implemented our approach in a tool called VISTA. Our empirical evaluation on 2,672 test cases spanning 86 releases of four web applications shows that VISTA is able to repair, on average, 81% of the breakages, a 41% increment with respect to existing techniques.