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Rules Of Three

TestFlix

karlo.smid@tentamen.hr

@karlosmid

blog.tentamen.eu

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About Me

  • Improving software tester
  • Zagreb, Croatia
  • Tentamen
  • Testival, Association for Software Testing

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The Problem

  • What is?
  • Why three?
  • Not two, four or five?
  • Does It work?
  • How often?
  • A lot of ?

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The Brain

  • Short memory
  • Working memory
  • Different: Read only vs read/write
  • Common: low and short
  • Theoretical concepts or models: cognitive psychology, neuroscience, neuropsychology
  • Models, all wrong but some useful

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The Brain

  • Working memory
  • Cognitive system
  • For Information
  • Limited storage and duration
  • Reasoning and guidance
  • For behaviour and decision making
  • Chunk, word, letter, digit, concept
  • Four to seven, depends on Chunk type

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Psychology

  • Humans like three options
  • Most ambitious (independent)
  • Most cautions (big company)
  • Middle way (side project)

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Jerry Weinberg Software Testing

  • Solution - needs three ways to fail - testing
  • Three possibilities - development
  • Three different interpretation - communication

​

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Three Strikes Then Refactor

  • Programming
  • Do not Do Not Repeat Yourself (DRY) until you need it in three different places

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Writing

  • Scene With Three Characters Or Events
  • More Humorous, Effective Satisfying
  • Any Other Number

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Survival

  • Three minutes without air
  • Three minutes in Icy water
  • Three hours in extreme heat or cold
  • Three days without water
  • Three weeks without food

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Military

  • ⅓ of force in action
  • ⅓ of force ready for action
  • ⅓ of force resting
  • circular

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Example Active 2 Samsung Watch

  • The Problem Charge It
  • 1. Heuristic: magnetic USB + USB socket adapter => nothing on screen
  • ??????Software Or Hardware Issue
  • 2. Heuristic: replace USB socket adapter => USB-C adapter and Macbook Pro
  • Oracle: After one hour press power on button, only sound
  • 3. Heuristic: Samsung S20 application
  • Oracles
  • screen no physical damage, Samsung App shows phone status data
  • Conclusion
  • screen software issue - Samsung Service Confirmed

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Recap

  • Working memory: four to seven
  • Three options: best, worst, middle
  • Constraint On Development Solutions: number three
  • Many disciplines
  • It works!

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Thank You!

karlo.smid@tentamen.hr

@karlosmid

blog.tentamen.eu