Wicked Good Ruby 2013 - Killing Fibonacci

Video of Presentation: http://confreaks.com/videos/2741-wickedgoodruby-killing-fibonacci

Testing is an important part of the development lifecycle of any software solution. It is particularly important in the Ruby community with lots of real and perceived pressure to test first, test often and test fully (or at least 90% coverage, right?). However, many Rubyists don't test... or don't test enough... or even worse: don't test well. I believe this is due, in large part, to a communal pressure to "be all about testing" but without some good, practical advice on how to do that... or even just how to get started with TDD. This presentation is a journey into the past... to guide and teach a fledgling TDDer 10 lessons on how to begin and succeed with TDD. The current me offers some much-needed counsel to an 8-years-ago version of me on how to approach TDD and begin to embrace it as a Good Thing™. I use the Fibonacci sequence as a backdrop of the lessons and how to build out a short application via TDD. Stay to the end, because there's a very interesting surprise in store!

Transcript

1. Killing Fibonacci A journey of 10 lessons about.me/drsharp
2. 2005 Danny’05
3. I wish... ...to show me the way 8 years ago... I had found a mentor...
4. Back to the Past
   Danny’05 gets a visit from Dan2013 Photo credit: http://www.scififx.com/wp-content/uploads/2013/04/back-to-the-future-delorean.jpg
5. 10 Lessons
6. The “Story”
   Suppose... it’s 2005... ! I work for InvestCorp and they want to improve their Stock Picker app. They heard about this "Retracement" thingy and something about Fibonacci as a way to figure out a predictor.
7. The “Story”
   As the software developer for InvestCorp, I was told that I needed to build a predictor algorithm that would be used by some front-end calculation code. It needs to use the Fibonacci sequence as a calculation for computing a predicted value.
8. Retracement
   See: http://en.wikipedia.org/wiki/Fibonacci_retracement
9. Retracement Levels
   See: http://stockcharts.com/school/doku.php?id=chart_school:chart_analysis:fibonacci_retracemen
10. The “Story”
    The Front-end team is anxious to deliver a prototype... soon. ! I’ve heard about this TDD thing, so I’m interested to give it a try. ! ...
12. HELP?!
    
13. Lesson 1
    Courage ! Conquer the Fear
14. “Dont’ be afraid.” ~ Mike Desjardins (WGR’13) Courage
15. Courage is being scared to death... and saddling up anyway. Photo credit: http://70sbig.com/wp-content/uploads/2011/03/John-Wayne-Cowboy-Poster.jpg
16. Courage So let’s “saddle up”!
17. Ok, but really... How do I start?
18. Lesson 2
    Find your peace
19. Peace Find your ‘Green’ Photo credit: http://www.giorgiosironi.com/2010/03/tdd-checklist-red-green-refactor-in.html
21. Tip
    Quick Check to Red
23. Ok, so How Fast? How Slow? Do I write lots of tests first? Or lots of code?
24. Lesson 3
    Baby Steps First
25. Baby Steps MVT Minimum Valuable Test Grab a happy path...
27. Tip
    Quick Check to Green
29. So let’s build Fibonacci...
31. Baby Steps Now grab another happy path...
33. I’m rockin’ now... Good momentum. Can’t I just keep coding and skip the tests?
34. Lesson 4
    Stay Focused
35. Stay Focused Find your Rhythm
36. Stay Focused Find your Rhythm Tension vs. Peace
37. Stay Focused Find your Rhythm Tension vs. Peace Minimize the Red Time
38. Stay Focused Find your Rhythm Tension vs. Peace Minimize the Red Time Don’t Stop the Tests!
39. So Keep Going! Stay Focused
41. Something doesn’t feel right. Are the tests telling me something?
42. Lesson 5
    Listen to your Tests!
44. Ugh! I don’t fully understand this. How can I design what I don’t understand?
45. Lesson 6
    Know your Domain
46. Understanding Maybe...
47. Understanding But first... ! Let’s “finish off” Fibonacci
49. WAIT! Can I do this? Just change it like this?!
50. Lesson 7
    Refactor from Green
51. Refactor
52. My tests just look like they are ‘vetting’ my code. Is that ok?
53. Lesson 8
    Behavior, not Implementation
54. Behavior Let your TDD’ing be exploration... discovery
55. Behavior The domain is really Stock Price Prediction. !
56. Behavior The domain is really Stock Price Prediction. ! Retracement is too technical. !
57. Behavior The domain is really Stock Price Prediction. ! Retracement is too technical. ! Fibonacci is an implementation detail. !
58. Behavior The domain is really Stock Price Prediction. ! Retracement is too technical. ! Fibonacci is an implementation detail. ! The UI team won’t know or care.
59. Behavior Change the RetracementPredictor to a StockPricePredictor ! Start with refactoring to a pure Fibonacci Calculator
61. This seems like a lot of work for very little code. Will I still get my production code done in time if I TDD it all?
62. Lesson 9
    Tenacity
63. Tenacity TDD is slower than cowboy-coding or even TLMD (Test Later...Maybe... Development) Unless...
64. Tenacity You are concerned with things such as ... !
65. • Quality • Expandability • Refactorability • Longevity • Understandability • Documentability • Team Members • Future Developers • Bug Detection/Repair • Coding Fearlessly
 See: http://www.onjava.com/pub/a/onjava/2003/04/02/javaxpckbk.html Tenacity IMNSHO, of course
66. Tenacity Mastering the Art
 and Rhythm of TDD
 requires tenacity. ! See: http://www.exampler.com/discipline-and-skill.html
67. Tenacity Mastering the Art
 and Rhythm of TDD
 requires tenacity. ! It is a skill... a discipline... ! See: http://www.exampler.com/discipline-and-skill.html
68. Tenacity Mastering the Art
 and Rhythm of TDD
 requires tenacity. ! It is a skill... a discipline... ! like anything else. See: http://www.exampler.com/discipline-and-skill.html
69. Tenacity “I thought: TDD is a cruel joke played upon me by smart people. I persisted because I trusted those people. ... [and] I got better at it.” ~ Sandi Metz (WGR’13)
71. Ok, but still... This whole TDD thing just seems like a waste of time. Why do it?
72. Lesson 10
    Don’t write code... Create Software!
73. Create Software See: http://manifesto.softwarecraftsmanship.org/ You aren’t paid
 to write code. !
74. Create Software See: http://manifesto.softwarecraftsmanship.org/ You aren’t paid
 to write code. ! You are paid
 to build software. !
75. Create Software See: http://manifesto.softwarecraftsmanship.org/ You aren’t paid
 to write code. ! You are paid
 to build software. ! Coding should be Craftsmanship
76. “Our job is not to write code but to build things... ! ... [to] materialize ideas.” ~ Matt Aimonetti (WGR’13) Create Software
77. Once more to the code ... But skipping to the end Create Software
84. NASDAQ: AAPL
 April 2013 - October 2013 Hmmmm
85. 10 Lessons 1. Courage - Conquer your Fear 2. Find your Peace 3. Baby Steps 4. Stay Focused 5. Listen to your Tests 6. Know your Domain 7. Refactor from Green 8. Behavior, not Implementation 9. Tenacity 10. Create Software
86. ~ Dale Carnegie Inaction breeds doubt and fear. Action breeds confidence and courage. ! If you want to conquer fear, do not sit home and think about it. Go out and get busy. Photo credit: http://www.nathanmagnuson.com/leading-others-the-dale-carnegie-way/
87. Photo credit:http://2.bp.blogspot.com/-0tBpuH9MVMQ/TzApxSLTyBI/AAAAAAAAC0M/ZEhtLUPjUvE/s1600/green-light.jpg
88. Thank You! about.me/drsharp