Generating Counterexamples in the form of Unit Tests from Hoare-style Verification Attempts

Unit tests that demonstrate why a program is incorrect have many potential uses, including localizing bugs (i.e., showing where code is wrong), improving test suites, and better code synthesis. However, counterexamples produced by failed attempts at Hoare-style verification (e.g., by SMT solvers) are difficult to translate into unit tests. We explain how to generate unit tests from counterexamples generated by an SMT solver and how this process could be embodied in a prototype tool. This process combines static verification techniques and runtime assertion checking.