The Impact of Equivalent Mutants - Mutation 2009
by Bernhard J.M. Gruen, David Schuler, Andreas Zeller

Mutation '09: Proceedings of the 3rd International Workshop on Mutation Analysis, Pages 192-199, April 2009.

ISBN: 9780769536712

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See also

More information is available at 10.1109/ICSTW.2009.37.


If a mutation is not killed by a test suite, this usually means that the test suite is not adequate. However, it may also be that the mutant keeps the program's semantics unchanged---and thus cannot be detected by any test. We found such equivalent mutants to be surprisingly common: In an experiment on the Jaxen XPath query engine, 8/20 = 40% of all mutations turned out to be equivalent. Worse, checking the equivalency took us 15~minutes for a single mutation. Equivalent mutants thus make it impossible to automatically assess test suites by means of mutation testing.
To identify equivalent mutants, we are currently investigating the impact of a mutation on the execution: the more a mutation alters the execution, the higher the chance of it being non-equivalent. First experiments assessing the impact on code coverage are promising.

BibTeX Entry

    title = "The Impact of Equivalent Mutants",
    author = "Bernhard J.M. Gruen and David Schuler and Andreas Zeller",
    year = "2009",
    month = apr,
    booktitle = "Mutation '09: Proceedings of the 3rd International Workshop on Mutation Analysis",
    location = "Denver, Colorado, USA",
    pages = "192--199",
    ISBN = "9780769536712",

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