Reducing Web Test Cases Aging by means of Robust XPath Locators

In the context of web regression testing, the main aging factor for a test suite is related to the continuous evolution of the underlying web application that makes the test cases broken. This rapid decay forces the quality experts to evolve the testware. One of the major costs of test case evolution is due to the manual effort necessary to repair broken web page element locators. Locators are lines of source code identifying the web elements the test cases interact with. Web test cases rely heavily on locators, for instance to identify and fill the input portions of a web page (e.g., the form fields), to execute some computations (e.g., by locating and clicking on buttons) and to verify the correctness of the output (by locating the web page elements showing the results). In this paper we present ROBULA (ROBUst Locator Algorithm), a novel algorithm able to partially prevent and thus reduce the aging of web test cases by automatically generating robust XPath-based locators that are likely to work also when new releases of the web application are created. Preliminary results show that XPath locators produced by ROBULA are substantially more robust than absolute and relative locators, generated by state of the practice tools such as FirePath. Fragility of the test suites is reduced on average by 56% for absolute locators and 41% for relative locators.