Destroy All Software - Episode Fast Tests With and Without Rails Review
The specs in the final solution abuses mock by mocking the ActiveRecord API. The expectation mocks update_attributes. He says the solution only depends on RSpec and specs run outside of Rails, so the specs run fast. The problem is that the dependency on Rails exists because of the coupling created by the mocking of ActiveRecord. The tests are now brittle and can break when you upgrade Rails if the active record API changes.