What is the difference between mocks and stubs in Rails testing?

What is the difference between mocks and stubs in Rails testing?

In Rails testing, mocks and stubs are both used to isolate tests, but they serve different purposes. A stub is used to provide predefined responses to method calls, while a mock is used to verify that certain methods were called with specific arguments.

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

Sure! If you have a method that makes an external API call, you can use a stub to simulate the response without actually hitting the API. This makes your tests faster and more reliable.

And what about mocks? When should I use them?

Mocks are useful when you want to ensure that a method is called during the test. For example, if you have a service object that sends an email, you can use a mock to verify that the email sending method was called with the correct parameters.

Are there any best practices for using mocks and stubs?

Yes! It's best to use stubs for methods that return data and mocks for methods that have side effects. Also, keep your tests focused and avoid overusing mocks to prevent brittle tests.