What are the differences between mocks and stubs in testing?

What are the differences between mocks and stubs in testing?

Mocks and stubs are both used in testing to isolate components, but they serve different purposes. Stubs provide predefined responses to calls made during the test, while mocks are used to verify interactions between components.

Can you give me an example of when to use a stub?

Sure! If you're testing a function that fetches user data from an API, you might use a stub to return a fixed user object instead of making an actual API call.

And what about mocks? When should I use them?

Mocks are useful when you want to ensure that a specific method was called with the correct parameters. For instance, if you're testing a service that sends notifications, you can mock the notification service to verify that it was called with the right message.

Are there any tools that can help with creating mocks and stubs?

Yes, there are several tools like Mockito for Java, Sinon.js for JavaScript, and unittest.mock for Python that can help you create mocks and stubs easily.