jest-async

To test asynchronous JavaScript with Jest, you can use async/await syntax and promise assertions like resolves and rejects to handle non-blocking operations reliably. This Skill provides patterns for writing clear tests for functions that return promises.

Jest fake timers allow you to test setTimeout and setInterval callbacks by mocking the timer functions. This Skill covers advanced timer manipulation to effectively test debounced and polled functions without waiting real time.

Testing event emitters and streams in Jest involves verifying event emission and data flow through your asynchronous code. This Skill provides patterns to ensure your non-blocking operations handle stream data and events correctly.

To handle promise rejections in Jest tests, use the rejects matcher to assert that a promise throws an error. This Skill demonstrates promise-based assertions to verify your API client correctly handles error responses.

Yes, you can use Jest to test API client responses and background jobs in Node.js environments. This Skill provides testing patterns to ensure background processing logic completes within expected timeframes and handles data reliably.

Your Jest test finishes early because it does not wait for the async callback to resolve. Using async/await or returning the promise ensures Jest waits for non-blocking operations to complete before ending the test.