| Regression testing is an expensive but necessary activity to validate that existing functionalities of a system still work correctly and have not been negatively affected by the changes made to the system. Meanwhile, UML models are widely used during software development, including when building a test model for a system under test (for instance using the Siemens TDE/UML CASE tool). In this context, we propose a regression test selection and prioritization approach based on analyzing changes made to UML test models. We derive a mapping between model elements (in the test model) and test cases in an existing test suite and then detect changes made to the UML test model to classify test cases into three categories: obsolete test cases (test cases that cannot be re-executed on the new version of the system), retestable test cases (test cases that need to be re-executed on the new version of the system), and reusable test cases (test cases that do not need to be re-executed on the new version of the system). Moreover, the retestable test cases are further prioritized according to the detected changes. Two prioritization criteria are considered, and can be used in isolation or in combination: increasing early fault detection ability of prioritized test cases, reducing the risk of not prioritizing some test cases early in the prioritization. Finally, a case study is performed to evaluate the usefulness of our regression test selection and prioritization approach. |
