Visual Testing
BackstopJS is a visual regression testing tool that compares screenshots of web pages or components across versions. It's particularly useful for component libraries and design systems where you need to verify that changes to shared components don't break visual consistency across many consumers. How BackstopJS Works
Clojure
ClojureScript brings Clojure's testing model to the browser and Node.js. The testing primitives — deftest, is, testing — work identically to Clojure. But the runtime environment is different: no JVM, different async semantics, and multiple possible test targets. shadow-cljs makes all of this manageable with a single configuration file.
Clojure
re-frame's unidirectional data flow — events → effects → db → subscriptions → views — makes applications predictable. It also makes them testable. Every piece of behavior in a re-frame app is a pure function or a data-driven side effect description. re-frame-test provides the tooling to test them without a running browser. What re-frame-test
Clojure
Example-based tests check specific cases. Property-based tests check invariants across hundreds of randomly generated inputs. test.check is Clojure's property testing library — a port of Haskell's QuickCheck — and it finds bugs that no developer thought to test for. Why Property-Based Testing Consider a sorting function. Example-based
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 defaults.
Test Automation
Testing effectful Haskell code is where the language's type system earns its reputation. By abstracting over effects — whether through MTL typeclasses or algebraic effect systems like Polysemy — you can run production code with a pure test interpreter. No mocking frameworks, no monkey-patching, just different interpreters for different environments.
Test Automation
Tasty is a composable test framework for Haskell. It doesn't replace HUnit, QuickCheck, or Hedgehog — it organizes them. Tasty provides a TestTree abstraction that lets you mix testing libraries, run tests in parallel, filter by name, and generate multiple output formats from a single test suite. The Core
Test Automation
HSpec is Haskell's most widely used test framework for unit and integration tests. Beyond basic describe/it blocks, it offers hooks, shared context, custom matchers, and tight integration with QuickCheck. This guide covers the patterns that matter for large test suites. Setup and Structure Refresher import Test.Hspec
Clojure
Babashka is a native Clojure scripting runtime that starts in milliseconds. It runs Clojure code without the JVM startup penalty, making it practical for scripts that need to run frequently — build tools, CI helpers, file processors, HTTP clients. But scripts grow complex, and complex code needs tests. This guide covers
Test Automation
Spock is a testing and specification framework for Java and Groovy applications. It combines JUnit's test runner compatibility with a highly expressive Groovy-based DSL. The result is tests that read like documentation and fail with clear, informative messages. Why Spock Spock's given/when/then structure maps
Test Automation
Spock's data-driven testing features turn a single spec into a parameterized test suite with almost no boilerplate. The where block, data tables, and @Unroll annotation work together to produce clear, readable test output for every data combination. The Where Block Add a where block to any feature method
Test Automation
Spock's built-in mocking eliminates the need for Mockito or PowerMock in most Groovy/Java projects. The API is concise, the error messages are clear, and the interactions integrate directly with the then block's assertion syntax. The Three Types Spock provides three mock variants with distinct purposes: