Mocking

Mocking

• Overview
  • SUT (“System under test”)
  • Collaborators (other objects needed to test SUT)
  • Decoupling is a major goal
• What is a Mock?
  • An object that stands in for another object during testing
  • Make sure that only the right methods are called
  • Other terms: doubles, stubs, and others. Don’t get confused.
• Advantages
  • Decoupling is always a good thing.
    • Performance
    • Maintainability
    • Testability
  • If you introduce a bug in a class
    • Only the tests that are testing that class will fail
    • So, fewer false positives
  • Disadvantages
    • Need to maintain to consistency between the mock and the class-being-mocked
    • Otherwise you may be testing somethingn that doesn’t even exist
• Coding example: Doubles Demo
• Refs:
  • Minimalicious Testing in Ruby
  • Great conceptual overview: Mocks aren’t Stubs