Safety-complete test suites

Abstract

In this paper, a novel safety-related variant of complete test suites for finite state machines is introduced. Under certain hypotheses which are similar to the ones used in the well-known W-Method or the Wp-Method, the new method guarantees to uncover every safety violation, while erroneous outputs without safety-relevance may remain undetected. In well-defined situations that can be precisely pre-determined from the reference model, this leads to a substantial reduction of test cases in comparison to the size of the analogous Wp-test suites. We advocate this new test suite for situations, where exhaustive testing of the complete system is too expensive. In these cases, strong guarantees with respect to fault coverage should only be given for the errors representing safety violations, while it is considered as acceptable if less critical errors remain undetected.