Testing Tools
Istanbul is the most widely used JavaScript code coverage tool. Its CLI wrapper nyc makes it trivial to add coverage instrumentation to any Node.js project. This guide covers setup, configuration, coverage thresholds, CI integration, and how to actually use coverage data to improve your tests. What Istanbul/nyc Measures
Testing
React Testing Library (RTL) has become the standard for testing React components. It replaced Enzyme as the go-to tool because it tests behavior, not implementation. If you're still testing internal state or calling component methods directly, you're doing it wrong — and RTL is here to fix
Testing
Storybook started as a UI development tool — a sandbox where you could render components in isolation and iterate on them without spinning up your whole application. That's still what most people use it for. But since Storybook 7, it has grown into a legitimate component testing platform. You
Testing
Jest is fast enough — until it isn't. Once your test suite crosses a few hundred tests, you start feeling it: the five-second startup, the transform overhead, the config file that has evolved into something no one fully understands. Bun's built-in test runner is a direct answer
Testing
If you've ever mocked an API by patching fetch, overriding axios.get, or wrestling with nock's obscure intercept API, you know the pain. Your mock and your real network call look nothing alike. The mock breaks when you refactor your fetching logic. And none of it