A Little Language for Testing

The difficulty of writing test harnesses is a major obstacle to the adoption of automated testing and model checking. Languages designed for harness definition are usually tied to a particular tool and unfamiliar to programmers; moreover, such languages can limit expressiveness. Writing a harness directly in the language of the software under test (SUT) makes it hard to change testing algorithms, offers no support for the common testing idioms, and tends to produce repetitive, hardto-read code. This makes harness generation a natural fit for the use of an unusual kind of domain-specific language (DSL). This paper defines a template scripting testing language, TSTL, and shows how it can be used to produce succinct, readable definitions of state spaces. The concepts underlying TSTL are demonstrated in Python but are not tied to it.