Agileee 2012
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The document discusses reversing the "tests pyramid" approach to address technical debt in legacy code. It notes that unit testing is difficult for code without separation of concerns, but refactoring without tests is risky. It proposes starting with high-level tests to gain confidence for refactoring into units and writing unit tests incrementally. However, end-to-end tests are long to maintain, and if needed, the architecture may be flawed. Reversing the tests pyramid and refactoring code in this way takes time but pays back technical debt and allows for sustainable changes. Beware of refactoring just for its own sake - focus on removing duplication and improving changeability.
Agileee 2012
- 1. Reversed Tests Pyramid Wiktor Żołnowski @streser http://www.agileszkolenia.pl http://codesprinters.com
- 2. Can you imagine perfect software?
- 3. It would be perfect to work with perfect software every day... But... Our everyday work looks a little bit different...
- 6. It's easy... For a perfectly coded application...
- 7. Not so easy for legacy code ● How to implement unit tests if we don't have any separated units? ● You need to refactor your code to test it but refactoring without tests is too risky... ● There is a difference between courage and stupidity.. ● Should we give up then and for example rewrite the whole application?
- 8. First of all... How did we get to this point?
- 9. It's all because of the Technical Debt
- 10. Technical Debt is evil! ● Sometimes it is to late to payback technical debt in a simple way... ● Success in Software Development is something which is not continuous... ● Success is state that you can achieve but also lose very fast if you can't respond to changes fast enough...
- 11. Is it possible to pay Technical Debt back?
- 13. Now refactor... ● High level tests gives you courage to refactor your code... ● You have to assume that the old version of the system works properly... ● Now you can write some Unit Tests... ● Do it step by step... ● Cover your functionality with Unit Tests...
- 14. But.. There are few reasons why you shouldn't reverse tests pyramid ● End-To-End tests are too long... ● End-to-end tests are difficult to maintain... ● If we need end-to-end tests we are probably doing something wrong with our architecture...
- 15. So it's all about reversing back our tests pyramid.
- 16. But... ● Remember that creating reversed tests pyramid and reversing it back will take some time... ● You need to deal with it if you want to pay back your technical debt... ● Return of investment will be visible soon...
- 17. 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!
- 18. Wiktor Żołnowski www.codesprinters.com Questions?