Slides from my presentation at DDD North 2022 at University of Hull on 3rd December. Evolutionary design, refactoring and testing so as to appear to be psychic in designing software systems, with the aid of Harry Houdini.

1. HowtobePsychic

2. heyhihello
derek graham @deejaygraham

4. https://ti.to/ne-bytes

5. ConfessionTime

6. Clickbait?

12. MaximumValue

13. Tradition!

14. newSystem();

15. if(exists)

16. “The need to be and feel in control
is so strong that individuals will
produce a pattern from noise to
return the world to a predictable
state.”
Whitson and Galinsky

17. B.D.U.F.

21. Incremental,
Iterative

22. Ad-hoc

24. "It is not necessary to change.
Survival is not mandatory."
W. Edwards Deming

25. "All Complex systems that work
evolved from simpler systems
that worked. If you want to build
a complex system that works,
build a simpler system first, then
improve it over time.”
John Gall

27. • Simple Design
• Small Steps
• Incremental
• Continuous
• Refactoring & Tests

28. WalkingSkeleton

30. $@?&%!FirstDraft

31. “Almost all good writing begins
with terrible first efforts”
Annie Lamott

32. Wait

33. Kaizen

34. Review

35. Process

36. • Review
• Reverse Engineer
• Imagine
• Small Steps
• Refactor
• Add Tests

37. Refactoring

38. Refactoring

39. • Encapsulate Var
• Extract Method
• Introduce Variable
• Rename Method
• Move Method

41. • Inspect
• Prepare
• Research
• Refactor
• Clean up

42. AllTheTests

43. TDD

44. • Micro tests
• Approval tests
• Contract tests

45. JustTest!!!

46. Whennottoevolve

47. Feeling
More
Psychic?

48. HarryHoudini’s
10Spooky
tipsfor
EvolutionaryDesign

49. #1SOLID

50. #2SimpleDesign

51. •Tests
•Duplication
•Clarity
•Smallest

52. Notice and
Improve the
Names of
Things

53. #3 Three C’s of Design

54. •Cohesion
•Coupling
•Connascence

55. Connascence

56. …achangeinonewouldrequirethe
othertobemodifiedinordertomaintain
theoverallcorrectnessofthesystem

58. #4Keyboard

60. #5Draw

61. 'The mind a great place to have
ideas but a terrible place for
keeping them'
- David Allen

65. #6Smell

67. #7Read

68. #8Deliberate
Practice

70. #9Steal

71. #10GetGoing

72. • Learning Hour
• Join an Ensemble
• Individual Practice
• Find a Mentor

73. Bad Judgement ->
Terrible Mistakes ->
Good Judgement

74. Finally…

75. • Fix most important thing
• Reduce cost of change
• Ctrl + Z

76. Ifindoubt…

77. • Add a test
• Remove
duplication
• Reduce scope
• Find a better
name

78. @deejaygraham