Combinatorial Testing for VDM

Combinatorial testing in VDM involves the automatic generation and execution of a large collection of test cases derived from templates provided in the form of trace definitions added to a VDM specification. The main value of this is the rapid detection of run-time errors caused by forgotten preconditions as well as broken invariants and post-conditions. Trace definitions are defined as regular expressions describing possible sequences of operation calls, and are conceptually similar to UML sequence diagrams. In this paper we present a tool enabling test automation based on VDM traces, and explain how it is possible to reduce large collections of test cases in different ways. Its use is illustrated with a small case study.