What are the differences between stubbing and mocking in testing?

What are the differences between stubbing and mocking in testing?

Stubbing and mocking are both techniques used in unit testing to isolate components. 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! You might use a stub when you want to simulate a database call that returns a fixed set of data without actually hitting the database.

And what about mocks? When should I use them?

Mocks are useful when you need to ensure that a specific method was called with the correct parameters. For example, if you're testing a service that sends an email, you can mock the email service to verify that the send method was called.

Are there any performance implications of using mocks and stubs?

Yes, using mocks and stubs can improve performance by avoiding slow operations like network calls or database queries, but excessive use can lead to complex tests that are hard to maintain.