How Much Should We Test?

Presented at SP Tech Talk

Transcript

1. HOW MUCH SHOULD WE TEST?
   Or how to stop hating your tests
   

   View Slide

2. GOALS OF TEST SUITE
   • Tests should be thorough
   • Tests should be stable
   • Tests should be fast
   • Tests should be few (minimal)
   

   View Slide

3. TEST DRIVEN DEVELOPMENT
   • We use test cases to guide the design of our code
   • 2 approaches to testing - Inside Out and Outside In
   • Outside In - Use integration tests to guide you
   • Inside Out - Build & test individual components, integrate later
   

   View Slide

4. View Slide

5. View Slide

6. Object under test
   

   View Slide

7. Object under test
   Incoming Messages
   

   View Slide

8. Object under test
   Incoming Messages Outgoing Messages
   

   View Slide

9. Object under test
   Incoming Messages Outgoing Messages
   

   View Slide

10. Object under test
    Incoming Messages Outgoing Messages
    Send to self
    

    View Slide

11. Object under test
    Incoming Messages Outgoing Messages
    Send to self
    Message Types:
    

    View Slide

12. Object under test
    Incoming Messages Outgoing Messages
    Send to self
    Query
    Message Types:
    

    View Slide

13. Object under test
    Incoming Messages Outgoing Messages
    Send to self
    Command
    Query
    Message Types:
    

    View Slide

14. MESSAGE TYPES
    • Query: Returns something / changes nothing
    • Command: Returns nothing / changes something
    Object under test
    Incoming Messages Outgoing Messages
    Send to self
    Command
    Query
    

    View Slide

15. View Slide

16. View Slide

17. View Slide

18. View Slide

19. View Slide

20. View Slide

21. RESOURCES
    • “The Magic Tricks of Testing”
    - Sandi Metz

    http://confreaks.tv/videos/railsconf2013-
    the-magic-tricks-of-testing
    • “Working Effectively with
    Unit Tests” - Jay Fields

    https://leanpub.com/wewut
    

    View Slide