Sinon.JS: Isolate and Inspect Code for Unit Tests
Sinon.JS lets you replace real functions with test doubles to check *if* and *how* they were called. Use it to fake network requests or control timers. The biggest footgun is forgetting to restore fakes, which causes tests to leak state and fail unpredictably.
Sinon.JS provides test doubles—fakes, spies, and stubs—to isolate code during unit tests. It replaces real dependencies like APIs or timers with controllable stand-ins you can inspect. It's essential for testing functions that make network calls or depend on `setTimeout`. The biggest footgun is forgetting `sinon.restore()`, which leaks fakes into other tests and causes confusing, cascading failures.
Read the original → sinonjs.org
- #javascript
- #testing
- #node.js
- #unit-testing
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