Mixed constraints for test input generation - An initial exploration

The use of specifications provides an effective technique to automate testing. A form of specification that automates generation of test inputs is logical constraints that define properties of desired inputs. Recent advances in constraint solving technology have made the use of constraints particularly attractive. However, manually writing constraints to define complex inputs to real-world programs can pose a significant burden on the user and restrict their wider use. We envision a novel approach to facilitate the use of constraints: to provide a mixed notation for writing the properties. Our key insight is that different properties can lend to easier formulation using different programming paradigms. Thus, a notation that supports more than one paradigm, e.g., declarative and imperative paradigms, can enable achieving a sweet-spot in minimizing the manual effort required in constraint formulation. Moreover, solving such constraints is also likely to be more efficient as different properties may require different paradigms for more direct and accurate representation. This paper presents our vision and gives an illustration to make a case for the usefulness of such a notation.