Clojure
Clojure's web stack — Ring for HTTP abstraction, Compojure for routing — is highly testable because it's built around plain functions and immutable data. A Ring handler is just a function from request map to response map. This means you can test your entire HTTP layer without starting
Clojure
Example-based tests verify that specific inputs produce specific outputs. They are good at documenting intended behavior and catching known regressions. What they cannot do is find the bugs you haven't thought of yet. Property-based testing flips the model: you describe invariants your code must always satisfy,
Clojure
Most Clojure developers learn deftest and is quickly, then stop. They write tests that look fine but miss the idioms that make large test suites maintainable, fast, and expressive. This post covers the patterns that separate workable test suites from great ones — fixtures that actually clean up, custom matchers that
Testing
Kaocha is the test runner that Clojure projects reach for when clojure.test and lein test stop being enough. It adds test suites, plugin architecture, a watch mode, and rich output formatting — while staying fully compatible with standard clojure.test tests. This guide covers the setup and patterns that matter
Clojure
re-frame's unidirectional data flow — events → effects → db → subscriptions → views — makes applications predictable. It also makes them testable.
Clojure
Example-based tests check specific cases. Property-based tests check invariants across hundreds of randomly generated inputs.
Clojure
Kaocha is the most flexible test runner in the Clojure ecosystem. While lein test and clojure -M:test get you started, Kaocha gives you fine-grained control over test selection, execution order, output formatting, and extensibility through plugins. This guide covers advanced Kaocha configuration for teams that need more than
Clojure
Babashka is a native Clojure scripting runtime that starts in milliseconds.
Clojure
Clojure's testing ecosystem is unusually rich for a language its size.