On testing of functionally equivalent components of fault-tolerant softwareSix functionally equivalent programs were tested with specification based random and extremal/special value (ESV) test cases. Statement and branch coverage were used to measure and compare the attained testing effectiveness. It was observed that both measures reached a nearly steady state value after 25 to 75 random test cases. Coverage saturation curves appear to follow an exponential growth model. However, the steady state values for branch coverage of different components, but the same input cases, differed by as much as 22 percent. The effect is the result of the differences in the detailed structure of the components. Improvement in coverage provided by the random test data, after the ESV cases were executed, was only about 1 percent. Results indicate that extensive random testing can be a process of diminishing returns, and that in the FTS context functional ('black box') testing can provide a very uneven execution coverage of the functionally equivalent software, and therefore should be supplemented by structure based testing.
Document ID
19880041835
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Vouk, Mladen A. (North Carolina State Univ. Raleigh, NC, United States)
Helsabeck, Michael L. (North Carolina State Univ. Raleigh, NC, United States)
Tai, Kuo-Chung (North Carolina State Univ. Raleigh, NC, United States)
Mcallister, David F. (North Carolina State University Raleigh, United States)