A Methodology for Applying Concolic Testing

Abstract: Concolic testing is a technique that combines concrete and symbolic execution in order to generate inputs that explore different execution paths leading to better testing coverage. Concolic testing tools can find runtime errors fully automatically using available type specifications. The type specifications in a function define the type of each input. However, most specification languages are never expressive enough, which can lead to runtime errors caused by malformed inputs (i.e. irrelevant errors). Moreover, logic errors causing a program to operate incorrectly without crashing cannot be reported automatically. A universal methodology for any programming language is proposed. Preconditions force the concolic execution to generate well formed inputs before testing a function. On the other hand, postconditions lead to a runtime error when a program operates incorrectly, helping to find logic errors. The results obtained using the concolic testing tool CutEr, in the functional programming language Erlang, show how a program is only tested using well formed inputs specially generated to try to violate the defined postconditions.