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Jdojo@Gbg Introduction


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Slides used at the first startup meeting of a series of coding dojo sessions, focusing on TDD mostly (Meetup group JDojo@Gbg)

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Jdojo@Gbg Introduction

  1. 1.
  2. 2. Bugs
  3. 3. The Problem● Bugs are costly● Fixing bugs reported from testers costs even more● Fixing bugs reported from en users costs even more than "even more"
  4. 4. What solution?
  5. 5. IBM & Microsoft Report ● 40 - 90% fewer bugs discovered during testing ● 15 - 35% more time spent on development
  6. 6. TDD vs Traditional TestingDoesnt remove theneed for regular,traditional testing:● Exploratory testing● QA testing● User Interface testing● Performance testing● ...
  7. 7. Test-Driven Developmemt Kent Beck on TDD: Im not a great programmer, Im just a good programmer with great habits.
  8. 8. Red, Green, Refactor ● Write a test, get it to compile, get a red bar ● Quickly make the test pass, get a green bar ● Refactor, "clean code", run tests frequently - the "bar" should stay green
  9. 9. Another Take ● write test first ● write smallest possible implementation ● clean up ➔ no "dead" code - its all covered ➔ nice API - designed outside in
  10. 10. Baby Steps● as small as possible● as large as is comfortable ● experience of TDD ● technology knowledge ● boldness ● understanding of the problem domain
  11. 11. 3A ● Arrange ● Act ● Assert
  12. 12. Benefits ● More confident ● More productive ● More reliable ● More agile
  13. 13. Drawbacks● More code to maintain● Takes longer● Easy to learn, but harder to master
  14. 14. JDojo@Gbg A safe environment to learn coding skills such as Test-driven Development and writing clean code
  15. 15. Dave Thomas - Kata"Pragmatic Dave":A kata is an exercise inkarate where you repeata form many, manytimes, making littleimprovements in each.
  16. 16. The Coders Dojo Concept presented at XP 2005 byLaurent Bossavi and Emmanuel Gaillot
  17. 17. Coding Dojo ● A moderator presents a kata ● Solve the kata, and ... ● Learn from others, teach what you know ● Short retrospective
  18. 18. Kata ● Small programming exercise - 1-2 hours ● Start from scratch ● Strictly test-driven ● Next time, start over and try new approach ● Practice until you master the kata
  19. 19. Dojo Rules● Dont criticize until we have a green bar● Strict usage of TDD● Everyones obligation to point out any non- TDD behaviour
  20. 20. JDojo@GbgFredrik Wendt
  21. 21. All vector art comes from Gnome base icon set, which is licensed under LGPL. Man on vacuum cleaner from tpp-bloggen. Firebug logotype from Baby Steps photo from seandreilinger at Picture of Dave Thomas from x180 at Picture of Kent Beck from Three Rivers Institute web site