PESTO: A Tool for Migrating DOM-Based to Visual Web Tests

Automated testing of web applications reduces the effort needed in manual testing. Old 1st generation tools, based on screen coordinates, produce quite fragile test suites, tightly coupled with the specific screen resolution, window position and size experienced during test case recording. These tools have been replaced by a 2nd generation of tools, which offer easy selection and interaction with the web elements, based on DOM-oriented commands. Recently, a new 3rd generation of tools came up based on visual image recognition, bringing the promise of wider applicability and simplicity. A tester might ask if the migration towards such new technology is worthwhile, since the manual effort to rewrite a test suite might be overwhelming. In this paper, we propose PESTO, a tool facing the problem of the automated migration of 2nd generation test suites to the 3rd generation. PESTO determines automatically the screen position of each web element located on the DOM by a 2nd generation test case. It then calculates a screenshot image centred around the web element so as to ensure unique visual matching. Then, the entire source code of the DOM-based test suite is transformed into a visual test suite, based on such automatically extracted images and using specific visual commands.