Maxim Koshtenko, an iOS developer with 5+ years of experience tells about: – what test-driven development is – advantages of TDD – how to use test-driven development for iOS projects – most common problems and solutions – how to start working with TDD on an existing project

1. Test-Driven !
Development

2. Debugging sucks!
Testing rocks!

3. Traditional flow
Design
Implement
Test

4. Test-driven flow
Design
Implement
Test

5. Test-driven flow
Design
Implement
Test
Test

6. Test-driven flow
Design
Implement
TestTest

7. Test-driven flow
Design
Implement
TestTest
Figure out what you want to do

8. Test-driven flow
Design
Implement
TestTest
Write a test to express the design
It should FAIL

9. Test-driven flow
Design
Implement
TestTest
Write the code

10. Test-driven flow
Design
Implement
TestTest
Test again
It should PASS

11. Add a test
Each new feature begins with writing a
test
Focus on the
requirements before
writing the code

12. Run all tests
Check that changes are required and test
passes only in intended cases

13. Write a code
Write simplest and inelegant code to make
test pass
Use hardcodes where
possible

14. Run tests
Adjust code until it meets the test
requirements

15. Refactor code
Cleanup your code!
Don’t worry, test covers you

16. What is TDD?
Red RefactorGreen
1. Write tests!
2. Implement changes!
3. Cleanup code

17. Bug fixing
1. Find bad code !
2. Turn it into a test !
3. Test should fail !
4. Fix bug !
5. Test should now pass

18. Advantages of TDD

19. Advantages of TDD
No more repeat bugs

20. Advantages of TDD
No more repeat bugs
Better design

21. Advantages of TDD
No more repeat bugs
Better design
Quick feedback

22. Advantages of TDD
No more repeat bugs
Better design
Quick feedback
Easy refactoring

23. Advantages of TDD
No more repeat bugs
Better design
Quick feedback
Easy refactoring
Great code coverage

24. YOU!
know !
TDD

25. Sources
http://www.amazon.com/Art-Unit-Testing-Examples-Net/dp/1933988274!
http://www.amazon.com/Test-Driven-iOS-Development-Developers-Library/dp/0321774183 !
http://www.objc.io/issue-1/testing-view-controllers.html!
http://qualitycoding.org/benefit-of-tdd/#more-2618!

27. Live Coding

28. https://github.com/maksumko/TDD-iOS-Demo