Foundations of software testing: dependability theory

Testing is potentially the best grounded part of software engineering, since it deals with the well defined situation of a fixed program and a test (a finite collection of input values). However, the fundamental theory of program testing is in disarray. Part of the reason is a confusion of the goals of testing---what makes a test (or testing method) "good." I argue that testing's primary goal should be to measure the dependability of tested software. In support of this goal, a plausible theory of dependability is needed to suggest and prove results about what test methods should be used, and under what circumstances. Although the outlines of dependability theory are not yet clear, it is possible to identify some of the fundamental questions and problems that must be attacked, and to suggest promising approaches and research methods. Perhaps the hardest step in this research is admitting that we do not already have the answers.