Abstract
Directed testing methods, such as functional or structual testing, have been criticized
for a lack of quantifiable results. Representative testing permits reliability
modeling, which provides the desired quantification. Over time, however, representative
testing becomes inherently less effective as a means of improving the actual quality
of the software under test.
A model is presented which permits representative and directed testing to be used in
conjunction. Representative testing can be used early, when the rate of fault
revelation is high. Later results from directed testing can be used to update the
reliability estimates conventionally associated with representative methods.
The key to this combination is shifting the observed random variable from the
interfailure time to a post-mortem analysis of the debugged faults, using order
statistics to combine the observed failure rates of faults no matter how those faults
were detected.
