test.check review

Reviewed by iTechGuides Editors · Editorial team · Updated Oct 2026

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.

test.check pros and cons

• 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

test.check fact sheet, pricing and score →

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Last updated 7 Oct 2026 · How we research and update