Differential Testing using Random Well-Typed Haskell Programs

Haskell is a statically-typed, purely functional programming language with a strong academic foundation, widely recognized for its application in both research and industry for developing robust, high-assurance software. Nowadays, it is being adopted for a variety of projects, where applications reach a level of complexity where manual testing and human inspection are insufficient to ensure quality in software development. Even in the presence of automated unit testing, such methodologies infrequently encompass the entirety of significant code scenarios, which means that certain defects may remain undetected, particularly when the code is subjected to an identical set of validation criteria repetitively. Considering this context, this paper describes a type system guided algorithm to generate random and well-typed Haskell programs, which can be used for testing the compiler, development tools, and libraries.