How to test code that depends on external APIs in Node.js

Unit testing code that interacts with external APIs presents challenges such as network-related issues, rate limits, and potential changes in API structure, but these can be mitigated by using strategies like mocking and recording API responses. The article discusses two popular methods for testing code that consumes third-party APIs, focusing on removing external dependencies to maintain fast and reliable tests. The first method involves manually mocking HTTP requests using Jest, which allows the test to simulate API responses without making actual network calls, although it requires careful maintenance to ensure the mock remains in sync with the real API. The second approach uses Nock to intercept API requests and record the responses for reuse, reducing the need for manual mock maintenance and avoiding potentially misleading results due to discrepancies between the mock and actual API. Both methods aim to decouple tests from external services, ensuring that tests remain speedy and deterministic, while also highlighting the importance of staying updated with any changes in the API's data structure to ensure test accuracy.