OBJTEST: an experimental testing tool for algebraic specifications

Algebraic specifications involve the development of `axioms´ or equations to model the behaviour of systems. The technique is one example of a formal method of specification. By using the equations to drive a process of term-rewriting, test expressions can be evaluated, thus providing an execution facility. Such animation certainly helps in checking typographical and notational errors. However, there is still a need for thorough testing of algebraic specifications to uncover more subtle errors. The author describes in outline, a prototype testing tool for algebraic specifications, OBJTEST, built around the ObjEx system. The two principal facets of the tool are the automatic generation of `exhaustive´ sets of test expressions from a specification, followed by the use of these test expressions in mutation testing of the given specification