Makina: a new QuickCheck state machine library

This article presents Makina, a new library and a domain specific language for writing property-based testing models for stateful programs. Models written in the new domain specific language are, using Elixir macros, rewritten into normal QuickCheck state machines. Our main goals with Makina are to facilitate the task of developing correct and maintainable models, and to encourage model reuse. To meet these goals, Makina provides a declarative syntax for defining model states and model commands. In particular, Makina encourages the typing of specifications, and ensures through its rewrite rules that such type information can be used by, e.g., the Dialyzer tool, to effectively typecheck models. Moreover, to promote model reuse, the domain specific language provides constructs to permit models to be defined in terms of collections of previously defined models.