What are the best practices for mocking fetch requests in testing?

What are the best practices for mocking fetch requests in testing?

When mocking fetch requests, it's important to ensure that your mocks accurately reflect the API's behavior. Use libraries like Jest or Sinon.

Can you give me an example of how to mock a fetch request using Jest?

Sure! You can use jest.mock to mock the fetch function. Here's a simple example:

jest.mock('node-fetch');
import fetch from 'node-fetch';

fetch.mockResolvedValueOnce({ json: jest.fn().mockResolvedValueOnce({ data: 'test' }) });

What should I do if the fetch request fails?

You can simulate a failed fetch request by using mockRejectedValueOnce. For example:

fetch.mockRejectedValueOnce(new Error('Network error'));

Are there any common pitfalls to avoid when mocking fetch?

Yes, avoid over-mocking. Ensure your tests still reflect real-world scenarios and consider edge cases.