Test your knowledge: unittest.mock

Review

1. What is the main purpose of using a Mock as a dependency in a unit test?

   A mock isolates a collaborator and records how it is used. The real behavior owned by the unit test should still execute.
2. A dependency should return the string "ready" whenever the mock is called. Which setting is appropriate?

   return_value sets the result returned by a mock call. side_effect is used for changing outcomes or raising exceptions.
3. A dependency should raise TimeoutError on its first call and return "ready" on its second. Which approach fits?

   An iterable side_effect supplies one result or exception for each successive call.
4. A module named billing imports fetch_rate from gateway, then calls fetch_rate() directly. Where should patch replace the lookup for a billing test?

   If the consumer imported the function into its own namespace, it looks up that local module attribute. Patch that consumer-side name.
5. What is a key benefit of create_autospec(real_function)?

   Autospeccing derives the mock interface from a real object and checks callable signatures, preventing some misspellings and incorrect argument lists.
6. Which practice usually makes unit tests more reliable and meaningful?

   Mocking too much couples tests to implementation details and can hide broken behavior. Keep the unit real and substitute selected collaborators.