Test Doubles - Setting Expectations with Mocks

This topic is for the [Setting Expectations with Mocks] exercise in the [Test Doubles] trail. Post any questions, corrections, or pointers you have to share with other Upcase subscribers.
[Setting Expectations with Mocks]: https://exercises.upcase.com/exercises/setting-expectations-with-mocks
[Test Doubles]: Test Doubles | RSpec Stub Online Tutorial by thoughtbot