Pragmatic TDD

As presented at Denver.rb on 3/11/14

Transcript

1. Pragmatic TDD Jeff Casimir / @j3
3. YATAT
4. About You
6. Everybody Uses TDD
7. Derailment #1 Deadlines!
8. Derailment #2 Tools Don’t Matter (that much)
9. ( BMW )
11. Derailment #3 Testing Makes 
 You Slower
12. Derailment #4 I just test by hand.
13. Reality:
 TDD is SCARY
14. Why?
15. Making Decisions 
 is Hard
16. Front-Loaded, 
 Conscious Decisions
17. Choose a Framework
18. Choose an Entry Point
19. The Paradox of Choice
20. What if you don’t choose?
21. Change choices consciously
22. Pragmatic TDD
 v0.1
23. Red, Green, Refactor
25. Let’s layout a 
 real strategy
26. 1. Why am I building 
 a thing?
27. 2. How will it ultimately 
 be used?
28. 3. What would they 
 name it?
29. 4. What inputs 
 does it need?
30. 5. How will I know 
 when it works?
31. 6. Are there
 edge cases?
32. 1. Why am I building a thing? 2. How will it ultimately be used? 3. What would they name it? 4. What kind of inputs does it need? 5. How will I know when it works? 6. Are there edge cases? TDD Strategy
33. Then dive into
 tactics
34. 1. Write a big test that summarizes the whole functionality.
35. 2. Run the big test, 
 see it fail.
36. 3. What’s the tiniest incremental step?
37. 4. What are the
 minimal inputs?
38. 5. What are the 
 expected outputs?
39. 6. Write the test
40. 7. See it fail
41. 8. Write an implementation
42. 9. Run the test. 
 Return to (8) if it fails.
43. 10. Run the big test.
 If it fails, go to (3).
 If it passes, you’re done!
44. 1. Write a big test 2. Run the big test 3. What’s the tiniest incremental step? 4. What are the minimal inputs? 5. What are the expected outputs? 6. Write the test 7. See it fail 8. Write an implementation 9. Run the test. If it fails, go to (8) 10. Run the big test. If it fails, go to (3), or else you’re done! TDD Tactics
45. Looks easy!
46. 1. Write a big test 2. Run the big test 3. What’s the tiniest incremental step? 4. What are the minimal inputs? 5. What are the expected outputs? 6. Write the test 7. See it fail 8. Write an implementation 9. Run the test. If it fails, go to (8) 10. Run the big test. If it fails, go to (3) TDD Tactics
47. Do try this at home.
 (not in front of all these people)
49. 1. Why am I building a thing? 2. How will it ultimately be used? 3. How would they name it? 4. What kind of inputs does it need? 5. How will I know when it works? 6. Are there edge cases? TDD Strategy
50. 1. Write a big test 2. Run the big test 3. What’s the tiniest incremental step? 4. What are the minimal inputs? 5. What are the expected outputs? 6. Write the test 7. See it fail 8. Write an implementation 9. Run the test. If it fails, go to (8) 10. Run the big test. If it fails, go to (3), or else you’re done! TDD Tactics
51. Pragmatic TDD Jeff Casimir / @j3