This document discusses emergent design and test-driven development using PHP and PHPSpec. It emphasizes designing software through describing how objects interact to solve problems, focusing on messaging between objects. Simple design rules like removing duplication and complexity are recommended to make code more testable, modular, and change-friendly. Designing for delegation using mocks is presented as a way to extract collaborators and move behavior definitions.

1. by@_md
emergentdesignwith

2. Iworkhere
Icontributehere
Itweethere @_md
MarcelloDuarte

3. it’s2007

4. @padraicb
@tswicegood

6. aportforrspec

7. !==
http://earthymoon.deviantart.com/art/Elephant-png-122633500 http://sonylisation.deviantart.com/art/Ruby-Nr-2-207831683

8. bowling.score.should eq(0)

9. inrubyeverythingisanobject
andallobjectsareopen
bowling.score.should eq(0)

10. inrubyeverythingisanobject
andallobjectsareopen
http://www.flickr.com/photos/owenbooth/126288240/
bowling.score.should eq(0)

11. inrubyeverythingisanobject
andallobjectsareopen
http://www.flickr.com/photos/owenbooth/126288240/
bowling.score.should eq(0)

12. $this->spec($bowling->getScore())
->shouldEqual(0);
PHPSPECEARLYSYNTAXEXAMPLE

13. http://www.flickr.com/photos/jamesrbowe/8403688026/
amber... red... green...

14. md@bossa:tests $ phpunit .
PHPUnit 3.7.14 by Sebastian Bergmann.
PHP Fatal error: Class 'Customer' not found
in /Users/mduarte/Documents/NoSync/Lab/phpunit/
tests/CustomerTest.php on line 8
Fatal error: Class 'Customer' not found in /
Users/mduarte/Documents/NoSync/Lab/phpunit/
tests/CustomerTest.php on line 8

15. yougottabemockingme!

16. public function testUpdateWithEqualTypes()
{
$installer = $this->createInstallerMock();
$manager = new InstallationManager('vendor');
$manager->addInstaller($installer);
$initial = $this->createPackageMock();
$target = $this->createPackageMock();
$operation = new UpdateOperation($initial, $target, 'test');
$initial
->expects($this->once())
->method('getType')
->will($this->returnValue('library'));
$target
->expects($this->once())
->method('getType')
->will($this->returnValue('library'));
$installer
->expects($this->once())
->method('supports')
->with('library')
->will($this->returnValue(true));
$installer
->expects($this->once())
->method('update')
->with($this->repository, $initial, $target);

17. @_md
@everzet

18. goals
{
funtoworkwith

19. goals
{developmenttool
funtoworkwith

20. goals
{developmenttool
let’snotgetintheway
funtoworkwith

21. goals
{enforce(mockist)TDD
developmenttool
let’snotgetintheway
funtoworkwith

22. goals
{enforce(mockist)TDD
doitthePHPway
developmenttool
let’snotgetintheway
funtoworkwith

24. {
"require-dev": {
"phpspec/phpspec": "2.0.*@dev"
},
"config": {
"bin-dir": "bin"
},
"autoload": {
"psr-0": {
"": "src"
}
}
}

25. $ bin/phpspec describe Some/Class$ bin/phpspec describe Some/Class

26. $ bin/phpspec describe Some/Class
$ bin/phpspec run
$ bin/phpspec describe Some/Class
$ bin/phpspec run

27. $ bin/phpspec describe Some/Class
$ bin/phpspec run
phpspec generators
$ bin/phpspec describe Some/Class
$ bin/phpspec run
phpspec generators

28. $ bin/phpspec describe Some/Class
$ bin/phpspec run
$ editor_of_choice . phpspec generators
$ bin/phpspec describe Some/Class
$ bin/phpspec run
$ editor_of_choice . phpspec generators

29. $ bin/phpspec describe Some/Class
$ bin/phpspec run
$ editor_of_choice . phpspec generators
$ bin/phpspec describe Some/Class
$ bin/phpspec run
$ editor_of_choice . phpspec generators

30. $ bin/phpspec describe Some/Class
$ bin/phpspec run
$ editor_of_choice . phpspec generators
$ bin/phpspec describe Some/Class
$ bin/phpspec run
$ editor_of_choice . phpspec generators

31. littledemo

32. emergentdesign

33. designemergeiterativelydrivenbytests

34. design
is
...

35. designsoftware
is
...

36. designsoftware
is
todescribehowwe’resolvingaproblem

37. calculatecostvarianceforaperiod

38. calculatecostvarianceforaperiod
Period

39. firstlearndesign,thenemergentdesign

40. “Key in making great and growable systems is to
design how its modules communicate
[andnot]whattheirpropertiesandbehavioursshouldbe.”
Messaging
ViewpointsResearchInstituteSource-BonnieMacbirdURL-http://www.vpri.org

41. messaging

42. $this->person->getCar()->getEngine()->ignite();

43. focusonmessaging
makesthecodeflexible

44. $this->person->startCar();

45. describinghowobjectsinteracttosolveproblems
whichroles,responsibilitiesandmessages
designsoftware
is

46. bigdesignupfront

47. IT’SHARDTOCHANGELATER.

48. WENEEDTOTHINKABOUTTHINGSBEFOREDEVELOPING.

49. WENEEDTOMAKESUREWEDON’TMISSANYTHING.

50. THISISJUSTTHEWAYWEDOIT.

51. relativecostofrepaircost
time
analysis design code test deploy rework
$

52. yagni

53. 61%
oftherequestedfeaturesareactuallydelivered
[Standish Group Report 06]

54. 27%
ofrequestedfeaturesareactuallyused

55. 5% to 10%
areresponsibleforrealisingthebenefitsenvisioned

56. designforthehighpriorityitems
andmakeiteasytochangelater

57. describinghowobjectsinteracttosolveproblems
whichroles,responsibilitiesandmessages
inachange-friendlyway
designsoftwareinagile
is

58. easiersaidthandone?

59. test
coderefactor

60. usesimpledesignrulestorefactor
1.Alltestsrunandpass
2.Removeduplication
3.Removeopacity
4.Removecomplexity

61. resultsincode
1.Testable
2.Modular
3.Expressive
4.Simple

62. lackoftestsbreaksinnerquality
1.Viscosity
2.Immobility,Rigidity,Fragility
3.Unreadable
4.Complex

63. simpledesignisgreattodetectsmells

64. simpledesign
1.Alltestsrunandpass
2.Removeduplication
3.Removeopacity
4.Removecomplexity
smells
1. Anytestssmells?
2.AnyDRYsmells?
3.Anyopacitysmells?
4.Anycomplexitysmells?

65. TestSmells
• Lackoftests
• Testsarenotunitary
• Setupistoocomplex
• Unclearexercise
• Morethanoneexpectationina
test
• Noexpectation
• Toomanypaths

66. DrySmells
• Simpleduplication
• Logicduplication
• Duplicationofconstant
• Alternativeclasseswithdifferentinterfaces

67. OpacitySmells
• Namenotfromdomain
• Namenotexpressingintent
• Featureenvy
• Methoddoesmorethanone
thing
• Methodtoolong
• Primitiveobsession
• Commentsinthecode
• MiddleMan

68. ComplexitySmells
• Unnecessaryelse
• Unnecessaryif
• Unnecessaryswitch
• Toomanyargumentspassed
• InappropriateIntimacy
• Workinconstruction
• Staticcontext

69. usedesignpatternstorefactor

70. creational?behavioural?structural?

71. whatcanhappeninamethod?

72. returnavalue
modifystate
printsomething
throwanexception
delegate
{methods

73. returnavalue
modifystate
printsomething
throwanexception
delegate
{methods
notthefinal
behaviour

74. returnavalue
printsomething
throwanexception
delegate{methods
weshouldprobably
delegatethattoo

75. returnavalue
throwanexception
delegate{methods

76. designdelegationwithmocks

77. startbydefiningbehaviour

78. internallydelegatetoanothermethod

79. Finally
• Definenewrole
• Extractcollaboratorsusingmocks
• Movebehaviourdefinitiontonewcollaboratortest

80. phpspec
emergentdesign
simpledesignandsmells
designingcompositionwithmocks

81. MarcelloDuarte
Iworkhere
Icontributehere
Itweethere @_md

82. Thankyou!

83. QuestionsorComments?
wanttolearnmore?bitly.com/inviqa-bdd-training
@_md joind.in/8459