For certain structural testing criteria a significant proportion of tests instances are infeasible in the sense the semantics of the program implies that test data cannot be constructed that meet the test requirement. This paper describes the design and prototype implementation of a structural testing system that uses a theorem prover to determine feasibility of testing requirements and to optimize the number of test cases required to achieve test coverage. Using this approach, we were able to accurately and efficiently determine path feasibility for moderately-sized program units of production code written in a subset of Ada. On these problems, the computer solutions were obtained much faster and with greater accuracy than manual analysis. The paper describes how we formalize test criteria as control flow graph path expressions; how the criteria are mapped to logic formulas; and how we control the complexity of the inference task. It describes the limitations of the system and proposals for its improvement as well as other applications of the analysis.

An automated verification system, Reacto-Verifier (RVF) developed for supporting the design of reliable reactive systems is described. In order to make the formal verification of large and/or complex systems tractable, RVF is enhanced by a knowledge-base manager, a proof manager, and a dependency maintenance procedure. The knowledge base manager supports a flexible use of a large set of axioms and rules derived from the domain theory of the specification language. The proof manager helps handle verification failure and supports off-line development of proofs. The dependency maintenance procedure permits the user to trace the history of a derivation and supports efficient addition and/or retraction of assumptions. RVF can be used both for batch-style automated verification, and for incremental development of verified programs.>