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test.check

Free#18 of 27 in Property-Based Testing Tools

test.check: A focused library for generated properties, shrinking, and reproducible failures. Ranked #18 of 27 in Property-Based Testing Tools by our editors (7.6/10); pricing: Free plan; best for clojure and ClojureScript teams.

7.6/10★★★★☆Editor score

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At a glance

• Editor score
  7.6 / 10
• Pricing
  Free plan
• Best for
  Clojure and ClojureScript teams
• Free plan
  Yes
• Paid from
  Free
• Supported languages
  Clojure, ClojureScript
• Facts checked
  20 Sep 2026

• Where it wins

  • Built-in generators and composable combinators for custom data
  • Automatic shrinking helps reduce failing generated cases
  • Seed replay and clojure.test and cljs.test integration

• Where it doesn't

  • Focused on Clojure and ClojureScript
  • Stateful testing is not part of its described scope
  • No paid tiers for differentiated feature levels

Our verdict on test.check

test.check is an open-source property-based testing library for Clojure and ClojureScript projects. It lets developers express universal properties that should hold across generated inputs, rather than writing only individual examples. Built-in generators cover common Clojure values, while generator combinators support custom data generation. The library integrates with clojure.test and cljs.test through defspec, making it a focused option for teams already working within those test frameworks.

Pricing is straightforward: test.check is open source and has a free plan. There are no paid tiers to compare, so the available capabilities center on the library itself rather than on feature differences between subscription levels. It is distributed as a project dependency through Clojure CLI, Leiningen, or Maven. Teams choosing it should be comfortable adding a library dependency and defining properties alongside their existing Clojure or ClojureScript tests.

Its standout capability is the combination of generated inputs, automatic shrinking, configurable test counts and maximum generated-value size, and seed-based replay. When a generated case fails, shrinking can automatically reduce it to a smaller failing example, while seed replay supports reproducing the test run. These features make test.check a good fit for teams seeking focused property-based coverage in Clojure ecosystems. It is less suitable for organizations seeking a broader multi-language tool or a solution with verified stateful testing. Choose it when generator-driven tests and reproducible failures are central requirements; consider an alternative when testing needs extend beyond its language and feature scope.

Your product? Our editors can test test.check in depth and publish a review, labelled as paid · from $149/mo →

test.check pricing

test.check fact sheet

Alternatives to test.check

• fast-checkA deep, runner-agnostic testing library for JavaScript and TypeScript teams.9.4
• HypothesisA focused Python library for generated inputs, shrinking, and stateful tests.9.3
• ProptestA focused Rust framework for generated inputs, shrinking, replay, and stateful tests.9.1

See all test.check alternatives →

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Featured on iTechGuides

Reviewed by iTechGuides Editors · Editorial team · Updated Oct 2026

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Last updated 7 Oct 2026 · How we research and update