Abstract

Unit tests are popular, but it is an art to write them in a way that specifies a program's behavior well and achieves high coverage of the program's possible execution paths. Symbolic execution is a new approach that can help. We introduce a set of techniques for unit testing based on symbolic execution. The techniques we describe can be used to increase path coverage by finding relevant variations of existing unit tests, or they can be used to generate unit tests from an implementation automatically when no prior unit tests exist. The adoption in commercial testing tools of techniques based symbolic execution has already begun.