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Measuring and Specifying Combinatorial Coverage of Test Input Configurations



David R. Kuhn, Raghu N. Kacker, Yu Lei


A key issue in testing is how many tests are needed for a required level of coverage or fault detection. Estimates are often based on error rates in initial testing, or on code coverage. For example, tests may be run until a desired level of statement or branch coverage is achieved. Combinatorial methods present an opportunity for a different approach to estimating required test set size, using characteristics of the test set. This paper describes methods for estimating the coverage of, and ability to detect, t-way interaction faults of a test set based on a covering array. We also develop a connection between (static) combinatorial coverage and (dynamic) code coverage, such that if a specific condition is satisfied, 100 % branch coverage is assured. Using these results, we propose practical recommendations for using combinatorial coverage in specifying test requirements, and for improving estimates of the fault detection capacity of a test set.
Innovations in Systems and Software Engineering


combinatorial testing, configuration model, covering array, fault coverage, state-space coverage, t-way testing, verification and validation (V&V)


Kuhn, D. , Kacker, R. and Lei, Y. (2015), Measuring and Specifying Combinatorial Coverage of Test Input Configurations, Innovations in Systems and Software Engineering, [online], (Accessed May 24, 2024)


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Created November 14, 2015, Updated November 10, 2018