Reversed Tests Pyramid - Agile Prague 2014
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The document discusses dealing with legacy code by implementing a "reversed tests pyramid" approach. It recommends starting with end-to-end tests to allow refactoring the codebase into a more testable structure before introducing unit and integration tests. While end-to-end tests are difficult to maintain, this process helps pay down technical debt over time by improving code quality and making the software easier to change. The key is to reverse the tests pyramid gradually through refactoring supported by tests at each level.
Reversed Tests Pyramid - Agile Prague 2014
- 1. Reversed TTeessttss PPyyrraammiidd –– DDeeaalliinngg WWiitthh LLeeggaaccyy CCooddee Wiktor Żołnowski @streser http://www.agileszkolenia.pl http://codesprinters.com @pragmaticcoders http://pragmaticcoders.com
- 2. Can you imagine perfect software?
- 4. Tests pyramid End to End Tests Functional/Integration Tests Unit Tests
- 5. It would be perfect to work with perfect software every day...
- 6. But!
- 7. Reality...
- 8. Is...
- 9. Different!
- 10. Legacy Code
- 11. How did we get to this point?
- 12. It's all because of the money...
- 13. Technical Debt
- 14. Sometimes Technical Debt could be considered as something good...
- 15. Unfortunately temptation of easy making money is huge...
- 16. People lives in illusion of continuous, fast and low cost development...
- 17. Forgetting about the Quality...
- 18. Success in Software Development is something which is not continuous...
- 19. Success is state that you can achieve but also lose very fast if you can't respond to changes fast enough...
- 20. So, is it possible to deal with legacy code?
- 21. Reversed Tests Pyramid End-to-End Tests Functional/Integration Tests Unit Tests
- 22. - What?!
- 23. You can't do unit testing when there are no units in your software...
- 24. You can't do integration tests when there is nothing to integrate...
- 25. You need to refactor your code so it would be testable...
- 26. How to refactor without tests?!
- 27. Now refactor... High level tests gives you courage to refactor your code... ●
- 28. But.. There are few reasons why you shouldn't reverse tests pyramid End-To-End tests are too long...
- 29. End-to-end tests are difficult to maintain... If we need end-to-end tests we are probably doing something wrong with our architecture...
- 30. So it's all about reversing back our tests pyramid.
- 31. Step by step we are introducing new architecture...
- 32. Remember that creating reversed tests pyramid and reversing it back will take some time...
- 33. But you need to do this if you want to pay your technical debt back!
- 34. Few final thoughts... Keep your technical debt as low as possible and try to pay it back every time you can. For example use your slack time for that!
- 35. Remember - WHY we are doing this?
- 36. “Leave the world better then you found it”
- 37. Beware of refactoring just for refactoring! Few final thoughts...
- 38. Few final thoughts... ● Beware of refactoring just for refactoring! ● Resist temptation to re-write from scratch – history is against you, such projects usually fail. ● Remember to always remove your (duplicated) tests! ● Software quality in many cases could be understood as ability to introduce changes into software! ● Keep your technical debt as low as possible and try to pay it back every time you can. For example use your slack time for that! Resist temptation to re-write from scratch – history is against you, such projects usually fail.
- 39. Few final thoughts... ● Beware of refactoring just for refactoring! ● Resist temptation to re-write from scratch – history is against you, such projects usually fail. ● Remember to always remove your (duplicated) tests! Remember to always remove your (duplicated) tests! ● Software quality in many cases could be understood as ability to introduce changes into software! ● Keep your technical debt as low as possible and try to pay it back every time you can. For example use your slack time for that!
- 40. False positive or false negative safety net is even worst than lack of safety net...
- 41. ● Software quality in many cases could be understood as ability to introduce changes into software!
- 42. Wiktor Żołnowski agileszkolenia.pl Questions? @streser http://pragmaticcoders.com http://codesprinters.com