Deriving Differential Unit Test Cases from System Test Cases

Differential testing works by creating test suites for both the original system and the modified system and contrasting both versions of the system with these two suites. Differential testing is made possible by recent advances in automated unit test generation. The differential unit testing is one where developers would like to generate tests that exhibit the behavioral differences between the two versions, if any differences exist. Differential unit tests (DUT) are a combination of unit and system tests. DUTs retain some of the advantages of unit tests, can be automatically and inexpensively generated, and have the potential for revealing faults related to intricate system executions. Some examples of differential unit testing include regression testing, N-version testing, and mutation testing. Differential testing discovered 21%, 34%, and 21% more behavior changes using regression testing techniques than using regression testing alone.