Resources

A curated list of talks, papers, and related projects for understanding property-based testing and the ideas behind Hedgehog.

Hedgehog family

• Haskell Hedgehog — The original implementation by Jacob Stanley. Hedgehog for OCaml follows the same design.
• Scala Hedgehog — Scala port with similar architecture.
• F# Hedgehog — F# port.
• Kotlin Hedgehog — Kotlin port.

Talks

• Gens N' Roses: Appetite for Reduction by Jacob Stanley — Explains why integrated shrinking matters and how rose trees make it work. This is the talk for understanding Hedgehog's design.
• Choosing properties for property-based testing by Scott Wlaschin — Practical advice on what properties to test.
• Building on Developers' Intuitions by John Hughes — From the creator of QuickCheck, on making PBT accessible.

Papers

• QuickCheck: A Lightweight Tool for Random Testing of Haskell Programs by Koen Claessen and John Hughes (2000) — The original QuickCheck paper.
• Finding Race Conditions in Erlang with QuickCheck and PULSE by Koen Claessen et al. — State machine testing for concurrency.
• Producing Wrong Data Without Doing Anything Obviously Wrong! by Alex Groce et al. — On the importance of good shrinking.

Books

• Property-Based Testing with PropEr, Erlang, and Elixir by Fred Hebert — Excellent practical introduction to PBT concepts, applicable across languages.
• The Joy of Kotlin by Pierre-Yves Saumont — Includes a chapter on property-based testing.

OCaml ecosystem

• QCheck — The established OCaml PBT library.
• ppx_quickcheck — Jane Street's PBT with ppx derivation.
• DSCheck — Model checking for concurrent OCaml programs.