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Refactoring When You Literally Can't Even

Refactoring When You Literally Can't Even

Refactoring is the process of changing the structure of a codebase without changing its external behavior. In addition to being an important part of ongoing development, it can also be used to get a legacy codebase under control.

Using the Gilded Rose Kata as a basis, this workshop explores how to refactor a legacy codebase safely, even when you don't yet understand what the code is doing.

Randy Coulman

May 12, 2016

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  1. www .codingzeal.com @codingzeal Randy Coulman a.k.a. Refactron Refactoring When You

    Literally Can’t Even Senior Software Engineer @randycoulman
  2. The System • Sell_in: the number of days we have

    to sell the item • Quality: how valuable the item is • End of each day: lower both values for every item
  3. The Spec: Can We Trust It? • Once the sell-by

    date has passed, quality degrades twice as fast • The quality of an item is never negative • “Aged Brie" actually increases in quality the older it gets • The quality of an item is never more than 50 • "Sulfuras", being a legendary item, never has to be sold or decreases in quality • "Backstage passes", like aged brie, increases in quality as its sell-by date approaches; quality increases by 2 when there are 10 days or less and by 3 when there are 5 days or less, but quality drops to 0 after the concert.
  4. Mob Programming • One computer for programming • One driver

    • N navigators and researchers http://mobprogramming.org/mob-programming-basics/
  5. What is Refactoring? “a disciplined technique for restructuring an existing

    body of code, altering its internal structure without changing its external behavior” http://refactoring.com
  6. When to Refactor? An ongoing part of your workflow Test-Driven

    Development (TDD) Cycle: Red -> Green -> Refactor
  7. Why Refactor? Ideal: Make the code look like it would

    have looked if the feature you just added had always been there
  8. Want More? Original Gilded Rose Kata http://craftsmanship.sv.cmu.edu/katas/gilded-rose-kata Gilding the Rose

    Talk at GoGaRuCo 2014 http://confreaks.tv/videos/gogaruco2014-gilding-the-rose-refactoring-legacy-code Code from GoGaRuCo 2014 Talk https://github.com/randycoulman/GildedRose
  9. References Working Effectively With Legacy Code: Michael Feathers http://www.amazon.com/Working-Effectively-Legacy-Michael-Feathers/dp/0131177052 Refactoring:

    Martin Fowler http://www.amazon.com/Refactoring-Improving-Design-Existing-Code/dp/0201485672 Refactoring Ruby Edition: Jay Fields, Shane Harvie, and Martin Fowler http://www.amazon.com/Refactoring-Ruby-Jay-Fields/dp/0321603508