Timo Stollenwerk gave a presentation on test-driven development (TDD) at a Python Barcamp in April 2013. TDD involves writing tests before writing code so that code is only written to pass failing tests, ensuring code works as intended. Following a TDD process results in code that works, is proven to work through testing, has a lower defect rate since it is tested, and is cheaper to fix bugs in. TDD also allows for shorter development cycles and a faster development process since testing is built-in, and makes development more satisfying and fun. Stollenwerk recommended following the practices of no code without a failing test, making the test pass quickly, then refactoring code and tests.

1. Test-Driven Development
Python Barcamp – April 2013
Timo Stollenwerk

2. Testing ???

3. Do not break things!
Timo Stollenwerk

4. What do we get?
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Code that works
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Proof that is works
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Lower defect rate
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Cheaper bug fixing

5. Test-Driven Development

6. Test-Driven Development

7. Test-Driven Development

8. Test-Driven Development

9. What do we get?
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Shorter development
cycles
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Fast development
process
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Satisfaction
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Fun!

10. No code without a failing test

11. Make test pass (quickly)

12. Test

13. Fix

14. Refactor

15. What do we get?
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Clean Code that
works
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Agile code

16. Testing Pyramid

17. Unit Testing

18. Integration Tests
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Schema
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Factory Type Info
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Factory
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Adding
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View

19. Functional Testing

20. Functional Tests
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„Second line of test
defense.“ (Martin
Fowler)
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Testable specification
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Failure in a
functional test >
missing unit test

21. Book Recommendations

22. Test-Driven Development
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Timo Stollenwerk