1. Test Driven Development Why I hate it, but really love it.

2. Start with FAIL

3. Make it Green!

4. Make it Pretty (refactor) (Not Like this chap)

5. Eh? Why??? How??? When???

6. WHY TDD?

7. Stability

8. Flexibility

9. Documentation

10. MORE SPEEEEDzzz

11. Design

12. HOW TDD? (Disclaimer: Code incoming!)

13. Writing an adding, er.. Thing… Failing Test: def test_add_1_plus_1 assert_equal 2, add(1,1) end Output: tdd.rb:6:in `test_add_1_plus_1': undefined method `add' for main:Object (NoMethodError) from tdd.rb:9

14. WHATS THE NEXT STEP?

15. Make it pass: def add(i,j) return 2 end Output: Loaded suite TddExample Started . Finished in 0.000455 seconds. 1 tests, 1 assertions, 0 failures, 0 errors

16. Waait!! Why isn’t it just: def add(i,j) return i+j end

17. WHATS THE NEXT STEP?

18. Write another failing test: def test_add_1_plus_2 assert_equal 3, add(1,2) End Loaded suite TddExample Started F Finished in 0.042739 seconds. 1) Failure: test_add_1_plus_1(TddExample) [tdd.rb:42]: <3> expected but was <2>. 1 tests, 1 assertions, 1 failures, 0 errors

19. Make it pass: def add(i,j) return i+j End Loaded suite TddExample Started .. Finished in 0.000462 seconds. 2 tests, 2 assertions, 0 failures, 0 errors

20. All about the baby steps

21. Problems?

22. add(1,2,3) Fail. add(1,”two”) Fail.

23. How do we cope?

24. Any number of arguments? First add a test.. def test_adding_three_arguments assert_equal 4, add(1,2,1) End Make it pass!! Add another test!! def test_adding_four_arguments assert_equal 8, add(1,2,1,4) end

25. Refactor For the general solution: def add(*args) return args.inject(0){|sum,n| sum + n} End Loaded suite TddExample Started .... Finished in 0.000941 seconds. 4 tests, 4 assertions, 0 failures, 0 errors

26. Dependency Injection (This has nothing to do with children)

27. Example: class PersonDAO def initialize(user, password) @data_source = Database.connect(user, password) end end VS class PersonDAO def initialize(data_source) @data_source = data_source end end

28. Why is this better?

29. And you’re telling me this… why?

30. Start off with a test def setup @person = FamilGuyDao.new end def test_return_full_name_is_reginald_von_griffen assert_equal "Reginald Von-Griffin", @person.full_name end #But how do we make it vary? Pass in the name? Pull it from somewhere #Lets assume there is some Griffin Family Tree in the sky def test_return_full_name_is_stewie_griffin assert_equal "Stewie Griffin", @person.full_name end

31. For now we’ll pass in the name

32. Next Test….

33. Make it pass…

34. WHATS THE NEXT STEP?

35. The General Case Integration faked by Mock object!

36. MAKE IT PASS!!

37. DONE!