Test case generation based on mutations over user execution traces

Abstract

Automatic test case generation is usually based on models of the software under test. However, those models may not exist or may be outdated and so, the test case generation must resort to other artifacts. In a software maintenance context, test cases must adapt to software changes and should be improved continuously to test adequately the new versions of the software. Mutation testing is a fault-based testing technique that evaluates the quality of the tests by applying simple changes to the source code and checking afterwards if the tests are able to detects those changes. This paper presents a web testing approach in which test cases are generated from user execution traces as a way to deal with the absence of models. In addition, it applies mutation operators over those test cases to enrich the test suite. The mutation operators were designed so as to mimic possible real failures. The additional tests are analyzed, and those that generate different outcomes are kept because they exercise additional behavior of the web application under test. At the end, the overall approach is illustrated and validated in a case study.