1. @gil_zilberfeld
Testing Economics 101
Gil Zilberfeld

2. @gil_zilberfeld
What is a professional developer?

3. @gil_zilberfeld
Who Am I?
Agile helper
Software improver
Author of “Everyday Unit Testing”
www.gilzilberfeld.com
www.everydayunittesting.com
@gil_zilberfeld

4. @gil_zilberfeld
A bit of history…
• Before there were testers…
• There was always risk
• There was always uncertainty
• It started to cost money

5. @gil_zilberfeld
And then came a tester
• The developer
• The bug catcher
• The gatekeeper

6. @gil_zilberfeld
A Tester
• Reports the state of the product
• Understands the risks
• Defines and maintains the test strategy
• Classifies test scenarios
• Finds ways to reduce risks
• Explores uncertain areas

7. @gil_zilberfeld
We are all testers!

8. @gil_zilberfeld
Macro Economics

9. @gil_zilberfeld
There are Testers in Team
• Testers as part of the team vs separate
• Longer communication
• Longer feedback cycle
• Collaboration and increased communication increases quality, reduces risks
and increases value
• Specialization vs. generalists
• Specialization can speed things up, or slow down when missing
• Organizations need to re-org to support specialization

10. @gil_zilberfeld
Bugs
• Bugs are waste by themselves
• Bug prioritization meetings
• More prevention, less mitigation
• Uncaught bugs can devalue a product
• The longer the feedback cycle, it takes longer to repro and fix
• Emergency bugs slow down development due to context switch

11. @gil_zilberfeld
Local Optimization
• Consider the whole process
• Improving at the right place
• Invest in the right things

12. @gil_zilberfeld
Testable Architecture and Design
• Unless planned and built, architecture is hard to change
• Need to be right the first time
• Cannot change, therefore slows development
• Build for testability

13. @gil_zilberfeld
Maintenance
• We write code that will last until the next rewrite
• Up to 20 years
• Tests are essential
• They delay the big rewrite
• Tests need maintenance too
• We can’t measure future maintenance, but can adapt good practices
to lower it

14. @gil_zilberfeld
Automation
• Automate checking
• Automate for testing
• Automation requires upgrading the testers

15. @gil_zilberfeld
Automated testing
With
Without

16. @gil_zilberfeld
2nd Cycle
With
Without

17. @gil_zilberfeld
Testing Strategy
• Understanding the risks
• Investing where it matters
• What to cover and how
• Take into account existing and needed skills
• Take into account existing and needed tools

18. @gil_zilberfeld
First to Market
• Cost of delay
• Damn the quality
• Still requires some testing
• More manual
• Less automation

19. @gil_zilberfeld
Micro Economics

20. @gil_zilberfeld
Debugging
• The biggest time waster there is
• With wonderful tools to help us
• But we’re solving the wrong problem

21. @gil_zilberfeld
TDD
• Thinking about coding before typing
• No YAGNI
• Creates testable systems, which cost less to maintain

22. @gil_zilberfeld
System Tests
• Better coverage, better confidence
• Cannot check edge cases
• Investment in setup
• Tests through UI are fragile
• Less for debugging and fixing problems, where unit tests work better

23. @gil_zilberfeld
Acceptance TDD
• Alignment and direction
• No YAGNI, just as TDD
• The collaboration matters, not the tools

24. @gil_zilberfeld
The ROI of Testing

25. @gil_zilberfeld
The Cost of Testing
• Salaries
• Infrastructure
• Licenses
• Training

26. @gil_zilberfeld
What Is The Value of Testing
• How do you measure the value of development?
• Number of features?
• Lines of code?
• Per minute?
• How do you measure the value of management?
• We don’t do that!

27. @gil_zilberfeld
ROI Is Dead!
• Complexity killed it
• ROI can be calculated only after the release
• And even that’s not true because the value of a product can impact
the next version or product

28. @gil_zilberfeld
The Real Value of Testing
• Early feedback
• Uncovering the unknown
• Identifying potential risks

29. @gil_zilberfeld
Summary
• Professionals understand economics
• Decide where to invest, what to drop

30. @gil_zilberfeld
Thank You!
• @gil_zilberfeld
• http://www.gilzilberfeld.com
• http://www.everydayunittesting.com