TDD and Related Techniques for Non Developers (2012)
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The document discusses Test Driven Development (TDD) and its importance for software developers, particularly those new to the field. It covers the steps involved in TDD, including writing tests, code refactoring, and integration, as well as the benefits and challenges associated with adopting this methodology. The author emphasizes the need for management support and continuous improvement in testing practices.
TDD and Related Techniques for Non Developers (2012)
- 1. Test Driven Development and Related Techniques For Non-Developers ;-) IBM 2012 Peter Kofler, ‘Code Cop’ @codecopkofler www.code-cop.org Copyright Peter Kofler, licensed under CC-BY.
- 2. Peter Kofler • Ph.D. (Appl. Math.) • (Java) Software Developer • with IBM since 1 year • SDM Costing, IGA, GBS
- 3. The opinions expressed here are my own and do not necessarily represent those of current or past employers.
- 4. Agenda 1) What does it look like? 2) Why is it important? 3) What you need to do! 4) Summary
- 5. 1) So what is it all about? The Prime Factors Kata (Demo)
- 6. What Exactly Will We Do Now? ● write code together ● using TDD ● see techniques and patterns ● discuss while doing
- 7. The Requirements. • Write a class named “PrimeFactors” that has one static method: generate. – The generate method takes an integer argument and returns a List<Integer>. – That list contains the prime factors in numerical sequence. http://butunclebob.com/ArticleS.UncleBob.ThePrimeFactorsKata
- 8. First Some Math. ● Prime Number: a natural number > 1 that has no divisors other than 1 and itself. ● e.g. 2, 3, 5, 61, 67, ..., 997, ..., 243112609-1, … ● Prime Factors: the prime numbers that divide an integer exactly without remainder. ● e.g. 2 = 2, 4 = 2 * 2, 24 = 2 * 2 * 2 * 3 288 = 25 * 32
- 9. The Requirements (for Mortals). • code a file/module/class “PrimeFactors” • code a function/method/routine “generate” • accept an integer number as parameter • return the prime factors of that number
- 10. Demo (Code Kata)
- 11. Keep the bar green to keep the code clean.
- 12. Unit Testing • test individual units • isolate each part • show that the individual parts are correct • regression testing • sort of living documentation • executed within a framework http://en.wikipedia.org/wiki/Unit_testing
- 13. Test-Driven Development • add a test • run all tests and see if the new one fails • write some code • run all tests and see them succeed • refactor code mercilessly • „Red Green Refactor“ http://en.wikipedia.org/wiki/Test_Driven_Development
- 14. A minute ago all their code worked
- 15. Refactoring Refactoring is a technique for restructuring an existing body of code, altering its internal structure without changing its external behavior. (Martin Fowler)
- 16. Refactoring • small behavior preserving transformations • sequence of transformations produce a significant restructuring • each transformation is small, less likely to go wrong • system is kept fully working after each change • verified by working tests
- 18. Code Coverage comprehensiveness of tests
- 20. Small Advice Never measure developers by Code Coverage!
- 22. Demo (Jenkins)
- 25. Continuous Integration • Maintain a code repository • Automate the build • Make the build self-testing • Everyone commits every day • Every commit should be built • Keep the build fast • Everyone can see the results of the build http://en.wikipedia.org/wiki/Continuous_integration
- 26. Immediate Feedback and Early Warning
- 27. Demo (Jenkins)
- 28. 2) Why should we use TDD? • Writing tests takes time • and we need to deliver client value. I don't have time. I don't have time. I don't have time.
- 29. Do you still use that one?
- 30. Discussion • What do you think are the benefits of TDD? – rapid feedback –… – ...
- 31. Benefits • speed up • coverage – measurable validation of correctness • quality – proven to save maintenance costs • creates a detailed specification
- 32. Benefits • improve design – drive the design of a program – think in exposed API
- 33. Problems • missing management buy-in • high ramp-up time • still need integration tests http://watirmelon.com/2012/01/31/introducing-the-software-testing-ice-cream-cone/
- 34. TDD will not fix missing skills! • badly written tests – brittle – blinking – slow – duplicate code – maintenance burden – wrong abstractions – not really unit tests
- 35. Because TDD is hard! • need to know OO, design, abstraction, ... • new style of thinking • need self-discipline • (learning curve)
- 36. 3) What you need to do
- 37. Problem Indicators: CI • blinking builds • builds broken for long time • increasing build execution time • decreasing code coverage
- 38. Problem Indicators: Tests • slow • fragile • no detailed feedback • “Ice-Cream Cone”
- 39. Problem Indicators: Developers • claiming that they can't write tests • claiming that they can't fix tests • wanting to delete tests
- 40. “Buzzwords” Summary • Techniques – Unit Testing – Test Driven Development – Refactoring – Code Coverage – Continuous Integration • Management Buy-In • Keep an eye on the CI server
- 41. Support TDD Do not compromise on techniques!
- 42. Thank You
- 43. Peter Kofler @codecopkofler www.code-cop.org
- 44. CC Images • Drive: http://www.flickr.com/photos/hjem/367306587/ • Judge: http://www.flickr.com/photos/eldave/6169431454/ • List: http://www.flickr.com/photos/kylesteeddesign/3724074594/ • Question mark: http://www.flickr.com/photos/oberazzi/318947873/ • Fence: http://www.flickr.com/photos/30830597@N08/3630649274/ • Coverage: http://www.flickr.com/photos/paulk/3166328163/ • Works: http://www.codinghorror.com/blog/archives/000818.html • Cash: http://www.flickr.com/photos/mindfire/315274981/ • Steep: http://www.flickr.com/photos/worldofoddy/229501642/ • Want You: http://www.flickr.com/photos/shutter/105497713/ • Warn: http://www.flickr.com/photos/hugosimmelink/2252095723/ • Questions: http://www.flickr.com/photos/seandreilinger/2326448445/