Advances in Lazy SmallCheck.

A property-based testing library enables users to perform lightweight verification of software. This paper presents improvements to the Lazy SmallCheck property-based testing library. Users can now test properties that quantify over first-order functional values and nest universal and existential quantifiers in properties. When a property fails, Lazy SmallCheck now accurately expresses the partiality of the counterexample. These improvements are demonstrated through several practical examples.