Following on from the learning hours on Stubs. Fakes are like stubs but with a real implementation.
Mark the true statements and not the other ones:
- A stub is a piece of code that doesn’t work yet
- A test double replaces a dependency of the class or function under test
- A stub behaves differently depending on the situation and the arguments it’s passed
- A test double is configured by a unit test to set up a specific situation for the class under test
- When you’re developing an API which another team will consume, you might give them a stub implementation of the API to work against.
- Test Doubles are not used in system testing, only unit testing
- Stubs are re-used in several test cases
- You can use a mocking framework to create both mocks and stubs
Concept - Fakes
Fakes are like stubs but they actually have a real implementation. Stubs just return hard-coded answers but Fakes do calculations, have state, and behave appropriately. Typical abstractions that you fake are files, queues, iterators, data stores.
Html Converter. First get them to read the code and establish which abstraction you want to replace with a test double. Make sure they have the documentation for the in-memory string version of a file for their programming language.
Get them to find the documentation for their language if you don’t have it.
Remind them to preserve the original constructor in addition to a new one that lets you inject the test double.
When should you use a Test Double? In particular, when should you use a Fake? Make some notes and share with the group.