An Introduction to XP and Agile


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An Introduction to XP and Agile

  1. 1. An Introduction to XP and Agile Jason Yip, [email_address] http://
  2. 2. What’s the problem?
  3. 3. Software takes too long , costs too much , and requires too many people
  4. 4. The plan is fantasy… and we don’t learn this until it’s too late
  5. 5. We’re wasting our lives doing things that don’t matter
  6. 6. Why do the problems occur?
  7. 7. We only have one opportunity to decide, so we ask for everything… and we waste time building what we don’t actually need
  8. 8. How often are features used?
  9. 9. We defer concrete validation until it’s too late to respond
  10. 10. We punish raising problems
  11. 11. We have too much specialisation
  12. 12. We have a “not my problem” culture
  13. 13. What do we want instead?
  14. 14. Any feature, any order, one at a time
  15. 15. Highest productivity, highest quality, lowest cost, highest morale
  16. 16. Real visibility about what’s happening
  17. 17. Learn about problems as early as possible
  18. 18. Less administrative work; more value-adding work
  19. 19. XP and Agile as a solution
  20. 20. Philosophy, Process, People, Problem Solving Problem Solving People Process Philosophy
  21. 21. Philosophy: Values <ul><li>Simplicity </li></ul><ul><li>Communication </li></ul><ul><li>Feedback </li></ul><ul><li>Courage </li></ul><ul><li>Respect </li></ul>
  22. 22. Software is too damned hard to spend time on things that don't matter. So, starting over from scratch, what are we absolutely certain matters? … Listening, Testing, Coding, Designing. That's all there is to software. Anyone who tells you different is selling something. Kent Beck,
  23. 23. Process: Just-in-Time
  24. 24. User Stories <ul><li>AS an Agile team member, I WANT a way to have self-contained small units of work SO THAT I can focus on one thing at a time, show visible progress earlier, and allow for negotiation </li></ul>
  25. 25. Card, Conversation, Confirmation <ul><li>Card – index card; physical token used for visual planning and tracking </li></ul><ul><li>Conversation – primary medium of communication supplemented as necessary with documentation </li></ul><ul><li>Confirmation – Examples that indicate when story is complete; turned into automated tests </li></ul>
  26. 26. Timeboxed iterative-incremental development
  27. 27. Small Releases
  28. 28. Process: Built-in Quality
  29. 29. Mistake proofing <ul><li>Eliminate – Don’t build it – YAGNI </li></ul><ul><li>Replace – Use a reliable library </li></ul><ul><li>Prevent by design </li></ul><ul><li>Facilitate – Only use the useful features, ignore the rest </li></ul><ul><li>Detect as early as possible – TDD, CI, pair programming </li></ul><ul><li>Mitigate – Make sure problems don’t cascade; error-handling </li></ul>
  30. 30. Test-driven Development <ul><li>Think </li></ul><ul><li>Red </li></ul><ul><li>Green </li></ul><ul><li>Refactor </li></ul><ul><li>Repeat </li></ul>
  31. 31. Continuous Integration
  32. 32. Pair Programming
  33. 33. People: T-shaped people
  34. 34. People: Whole Team
  35. 35. Authority vs Responsibility
  36. 36. Problem Solving: Daily Standups <ul><li>What did I accomplish yesterday? </li></ul><ul><li>What will I do today? </li></ul><ul><li>What obstacles are impeding my progress? </li></ul>http://
  37. 37. Problem Solving: Retrospectives <ul><li>What did we do well, that if we don’t discuss we might forget? </li></ul><ul><li>What did we learn? </li></ul><ul><li>What should we do differently next time? </li></ul><ul><li>What still puzzles us? </li></ul>http:// /
  38. 38. Problem Solving: Spikes over speculation <ul><li>&quot;What is the simplest thing we can program that will convince us we are on the right track?“ </li></ul><ul><li>Ward Cunningham </li></ul>
  39. 39. Why should we believe this will work?
  40. 40. This is the evolution of what we’ve learned over decades <ul><li>“ Although many view iterative and incremental development as a modern practice, its application dates as far back as the mid-1950s.” </li></ul><ul><li>Craig Larman and Victor R. Basili </li></ul>
  41. 41. Don’t believe… think for yourself… try something… see what happens… adjust
  42. 42. For some more conventional introductions… <ul><li> </li></ul><ul><li> </li></ul><ul><li> </li></ul><ul><li>http:// / </li></ul>