Talk in GopherconSG 2017

1. TDD
for people who don’t need it
@choonkeat 2017.gophercon.sg

2. Write
Tests
PSA
(Not to scale)
TDD
Write good
code
(Public Service Announcement)

3. TDD Community
warning: generalisation

5. TDD Community
• is irritating
• shames people
• doesn’t have your deadline
warning: generalisation

6. They say Tests
• Gives you confidence to refactor
• Helps you write better designed API
• Serves as documentation
• Untested code is legacy code
warning: ymmv

7. • Gives you confidence to refactor
• Helps you write better designed API
• Serves as documentation
• Untested code is legacy code
I have a YUGE confidence.
They say Tests
warning: ymmv

8. • Gives you confidence to refactor
• Helps you write better designed API
• Serves as documentation
• Untested code is legacy code
I have a YUGE confidence.
They say Tests
warning: ymmv

9. • Gives you confidence to refactor
• Helps you write better designed API
• Serves as documentation
• Untested code is legacy code
I have a YUGE confidence.
My code is well designed. Unlike yours.
They say Tests
warning: ymmv

10. • Gives you confidence to refactor
• Helps you write better designed API
• Serves as documentation
• Untested code is legacy code
I have a YUGE confidence.
My code is well designed. Unlike yours.
They say Tests
warning: ymmv

11. • Gives you confidence to refactor
• Helps you write better designed API
• Serves as documentation
• Untested code is legacy code
I have a YUGE confidence.
My code is well designed. Unlike yours.
My commit log is more awesome than your résumé
They say Tests
warning: ymmv

12. • Gives you confidence to refactor
• Helps you write better designed API
• Serves as documentation
• Untested code is legacy code
I have a YUGE confidence.
My code is well designed. Unlike yours.
My commit log is more awesome than your résumé
They say Tests
warning: ymmv

13. • Gives you confidence to refactor
• Helps you write better designed API
• Serves as documentation
• Untested code is legacy code
I have a YUGE confidence.
My code is well designed. Unlike yours.
My commit log is more awesome than your résumé
Untested test is legacy code too
They say Tests
warning: ymmv

14. God Himself
"regression testing"?
What's that?

15. "regression testing"?
What's that? If it
compiles, it is good,
if it boots up it is
perfect
Linus
God Himself

16. TDD Community
don’t understand that…

17. We ♥ Code Too
• Refactor & agonize over naming; like your first born
• Write commit messages like the world care to read
• Write inline docs that formats like professionals
• Recite design patterns before bedtime

18. They say Tests
• Gives you confidence to refactor
• Helps you write better designed API
• Serves as documentation
• Untested code is legacy code
warning: ymmv

19. They say Tests
• Gives you confidence to refactor
• Helps you write better designed API
• Serves as documentation
• Untested code is legacy code
warning: ymmv
YAGNI

20. I get paid for code
that works, not for
tests
- Kent Beck
Other God

21. Get shit done

22. Something to be done;
Do it

23. Something to be done;
Do itMachinery
Requirement

24. Machinery
= make shit happen

25. Requirements
= where constipation
happens

26. Requirements
= where constipation
happens
The Problem

27. [status check]

28. Job Interview

29. an 🤔 experience

30. http://railscasts.com/episodes/275-how-i-test

31. “I really like this approach
of testing, it just walks you
through: what’s the next
step I have to do to get
this working.”
http://railscasts.com/episodes/275-how-i-test

32. Machinery
&
Requirements

33. Machinery
= make shit happen

34. Machinery
= make shit happen
Master your
tools

35. Requirements
= usually hand-wavy,
high-level description of
expected output

36. Requirements
= usually hand-wavy,
high-level description of
expected output
Write it down

37. Requirements
= usually hand-wavy,
high-level description of
expected output
Use code

38. Requirements can
sometimes come at
different times, via
different channels,
evolving in response
new information

39. Requirements can
sometimes come at
different times, via
different channels,
evolving in response
new information
One copy;versioned

40. flickr.com/photos/eugeniowilman

41. flickr.com/photos/eugeniowilman
Requirement

42. flickr.com/photos/eugeniowilman
Requirement
Mechanism

43. flickr.com/photos/eugeniowilman
Requirement
Mechanism

44. flickr.com/photos/eugeniowilman
Requirement
Mechanism

45. Job Interview

46. [walk through code]

47. [walk through test]

61. ./edit_test.go:36: undefined: handleNewAddressRequest
./edit_test.go:47: undefined: addressFromMail
./edit_test.go:53: undefined: addressFromDB
./edit_test.go:59: undefined: visitLinkFromEmailTo
./edit_test.go:65: undefined: addressFromDB
FAIL choonkeat/gopherconsg/changeemail [build failed]

62. ./edit_test.go:36: undefined: handleNewAddressRequest
./edit_test.go:47: undefined: addressFromMail
./edit_test.go:53: undefined: addressFromDB
./edit_test.go:59: undefined: visitLinkFromEmailTo
./edit_test.go:65: undefined: addressFromDB
FAIL choonkeat/gopherconsg/changeemail [build failed]
Hungry?
Go Where?

63. ./edit_test.go:47: undefined: addressFromMail
./edit_test.go:53: undefined: addressFromDB
./edit_test.go:59: undefined: visitLinkFromEmailTo
./edit_test.go:65: undefined: addressFromDB
FAIL choonkeat/gopherconsg/changeemail [build failed]

64. ./edit_test.go:47: undefined: addressFromMail
./edit_test.go:53: undefined: addressFromDB
./edit_test.go:59: undefined: visitLinkFromEmailTo
./edit_test.go:65: undefined: addressFromDB
FAIL choonkeat/gopherconsg/changeemail [build failed]Pager duty?

65. Fire drill?

66. Baby cries?

67. ?

68. ./edit_test.go:47: undefined: addressFromMail
./edit_test.go:53: undefined: addressFromDB
./edit_test.go:59: undefined: visitLinkFromEmailTo
./edit_test.go:65: undefined: addressFromDB
FAIL choonkeat/gopherconsg/changeemail [build failed]

69. What’s next
What’s next
What’s next
What’s next
What’s next
What’s next

70. What’s next
What’s next
[requirement
change]What’s next
What’s next
What’s next
What’s next

71. Pass

72. Done

73. nasa.gov
You solve one problem...

74. nasa.gov
You solve one problem... and you solve the next
one…

75. nasa.gov
You solve one problem... and you solve the next
one... and then the next.

76. nasa.gov
You solve one problem... and you solve the next
one... and then the next. And if you solve enough
problems, you get to come home.
- Mark Watney

77. Get started

78. Don’t be distracted

80. Don’t WORRY
• Testing “Right”
• Testing All The Things — Rabbit hole
• Discarding tests
• Which test library to choose
• Should I mock or stub or factory — I don’t know I
don’t care

82. end