Let's have a close look into the Red-Green-Refactor cycle and understand the subtleties of each step. When we go down the rabbit hole of Test Driven Design we sometimes take too big steps leading us to many failed tests we just can bring back to green without writing a lot of code. We need to take a step back and take the shrinking potion of baby steps again. This very illustrative talk, full of test and code examples, will dig into each of the steps of TDD to help you understand how to keep a sustainable pace that will lead you in the right track.

1. TEST,
Test,
Test,
Test,
Test,
TRANSFORM,
Transform,
Transform,
Transform,
REFACTOR
Refactor
Refactor
Refactor
Refactor
PHPUK 2014
by @_md

2. Learning
@_md
Marcello Duarte
Lead developer
Head of Training
Kata sensei

3. @_md
Marcello Duarte
Lead developer
Head of Training

4. Kata
form
movement
practice
deliberate

5. 20 minutes
throw away
TDD
refactor
Kata

6. Test
Refactor
Code

7. no code without test
TDD
3Rules
enough to go red
enough to go green

8. no code without test
Test
enough to go red
Code
enough to go green

9. Refactor
tests run and pass
dry
sign remove opacity
De
ple
Sim
simplify
4Rules

10. The Roman Numerals Kata

11. Converting arabic numbers into their
roman equivalent
!
e.g. 2149 => MMCXLIX

12. Test
Make it red
Code
Make it green
Refactor
Make it right

13. The Roman Numerals Kata gone wrong
demo

14. Introducing TPP

15. Test
Make it more specific
Transform
Make it more generic
Refactor
Put on the design hat

16. null to constant
constant to constant+
constant to scalar
statement to statements
unconditional to if
if to while
Transformations (just the most basic ones)

17. * in PHP
http://www.flickr.com/photos/jorendegroof/4471189540/
Jim Weirich’s Roman Numeral Kata*

20. Walking skeleton
[Cockburn 94]

24. Transformation
null -> constant

30. Transformation
unconditional -> if

35. Transformation
statement -> statements

40. Transformation
unconditional -> if

45. Refactor time?

60. Transformation
if -> while

61. Condition to loop transformation
!
is a great indicator you are in the
right track of solving the algorithm
[Martin 13]

79. Katas and Learning

80. Kata
Deliberate Practice
Koan
Deliberate Learning
• Optimising for performance • Optimising for discovery
• Minimising variance
• Maximising variance
[North 12]

81. Learning TDD is learning
all that TDD does for you

82. “The beauty of a move lies not in its'
appearance but in the thought behind it.”

83. My System
elements of chess
positional play
illustrative games

84. First learn the elements of design
Then learn how to drive it with test

85. Marcello Duarte
we are hiring
try phpspec!
follow @_md

86. inviqa.com/tdd-immersion-day/

87. Thank you !

88. Questions or Comments?
joind.in/10711
@_md
want to learn more? inviqa.com/tdd-immersion-day/