Skip to content

Instantly share code, notes, and snippets.

@oinak
Created January 23, 2015 18:50
Show Gist options
  • Save oinak/33651dc2c34dffa6983f to your computer and use it in GitHub Desktop.
Save oinak/33651dc2c34dffa6983f to your computer and use it in GitHub Desktop.
Guilded Rose Kata al WeArePeople

The Gilded Rose Code Kata

This is a Ruby version of the Gilded Rose Kata, found [here](http://www.iamnotmyself.com/2011/02/13/RefactorThisTheGildedRoseKata.aspx I Am Not Myself).

This is a refactorying kata, so you will be starting with a legacy code base. To work the Kata, clone this git repository and checkout the tag 'start-here'. Read the description below for the "rules" involving this kata.

Changes from the original

This Ruby version follows the original code very closely, but has the following changes:

  • The original had no tests. Since this is a refactoring kata, I felt the tests were important and provide a fairly complete test suite. Just delete the tests if you wish to "go it alone".

  • The original used a hard coded set of "items", presumably for testing the code. Since I a test suite, the hard coded values were not of much use. I also changed the interface to accept a list of items as a parameter rather than a hard coded constant.

You can read [the original kata article](http://www.iamnotmyself.com/2011/02/13/RefactorThisTheGildedRoseKata.aspx I Am Not Myself) for more details.

Git Branches

  • The 'master' branch contains the starting point for the kata. It is also tagged as 'start-here'.

  • The 'solution1' branch is my first solution for this kata.

Hope you enjoy this. -- Jim Weirich

Original Description of the Gilded Rose

Hi and welcome to team Gilded Rose. As you know, we are a small inn with a prime location in a prominent city ran by a friendly innkeeper named Allison. We also buy and sell only the finest goods. Unfortunately, our goods are constantly degrading in quality as they approach their sell by date. We have a system in place that updates our inventory for us. It was developed by a no-nonsense type named Leeroy, who has moved on to new adventures. Your task is to add the new feature to our system so that we can begin selling a new category of items. First an introduction to our system:

  • All items have a SellIn value which denotes the number of days we have to sell the item
  • All items have a Quality value which denotes how valuable the item is
  • At the end of each day our system lowers both values for every item

Pretty simple, right? Well this is where it gets interesting:

  • 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 it's SellIn value 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

We have recently signed a supplier of conjured items. This requires an update to our system:

  • "Conjured" items degrade in Quality twice as fast as normal items

Feel free to make any changes to the UpdateQuality method and add any new code as long as everything still works correctly. However, do not alter the Item class or Items property as those belong to the goblin in the corner who will insta-rage and one-shot you as he doesn't believe in shared code ownership (you can make the UpdateQuality method and Items property static if you like, we'll cover for you). Your work needs to be completed by Friday, February 18, 2011 08:00:00 AM PST.

Just for clarification, an item can never have its Quality increase above 50, however "Sulfuras" is a legendary item and as such its Quality is 80 and it never alters.

class DefaultItem
attr_reader :item
def initialize(item)
@item = item
end
def update
update_sell_in
update_quality
end
protected
def update_sell_in
item.sell_in -= 1
end
def update_quality
item.quality -= (item.sell_in < 0 ? 2 : 1) if item.quality > 0
end
end
class Sulfuras < DefaultItem
def update_quality
end
def update_sell_in
end
end
class AgedBrie < DefaultItem
def update_quality
item.quality += (item.sell_in < 0 ? 2 : 1) if item.quality < 50
end
end
class Backstage < DefaultItem
def update_quality
if item.sell_in < 0
item.quality = 0
else
item.quality += quality_increase if item.quality < 50
end
end
private
def quality_increase
increase = 1
increase += 1 if item.sell_in < 10
increase += 1 if item.sell_in < 5
increase
end
end
class Conjured < DefaultItem
def update_quality
item.quality -= 2 if item.quality > 0
end
end
module ItemUpdater
CLASS_NAMES = Hash.new(DefaultItem).merge(
'Aged Brie' => AgedBrie,
'Backstage passes to a TAFKAL80ETC concert' => Backstage,
'Sulfuras, Hand of Ragnaros' => Sulfuras,
'Conjured Mana Cake' => Conjured
)
def self.factory(item)
CLASS_NAMES[item.name].new(item)
end
end
def update_quality(items)
items.each { |item| ItemUpdater.factory(item).update }
end
# DO NOT CHANGE THINGS BELOW -----------------------------------------
Item = Struct.new(:name, :sell_in, :quality)
# We use the setup in the spec rather than the following for testing.
#
# Items = [
# Item.new("+5 Dexterity Vest", 10, 20),
# Item.new("Aged Brie", 2, 0),
# Item.new("Elixir of the Mongoose", 5, 7),
# Item.new("Sulfuras, Hand of Ragnaros", 0, 80),
# Item.new("Backstage passes to a TAFKAL80ETC concert", 15, 20),
# Item.new("Conjured Mana Cake", 3, 6),
# ]
require 'rspec/given'
require 'gilded_rose'
describe "#update_quality" do
context "with a single" do
Given(:initial_sell_in) { 5 }
Given(:initial_quality) { 10 }
Given(:item) { Item.new(name, initial_sell_in, initial_quality) }
When { update_quality([item]) }
context "normal item" do
Given(:name) { "NORMAL ITEM" }
context "before sell date" do
Then { item.quality.should == initial_quality-1 }
Then { item.sell_in.should == initial_sell_in-1 }
end
context "on sell date" do
Given(:initial_sell_in) { 0 }
Then { item.quality.should == initial_quality-2 }
Then { item.sell_in.should == initial_sell_in-1 }
end
context "after sell date" do
Given(:initial_sell_in) { -10 }
Then { item.quality.should == initial_quality-2 }
Then { item.sell_in.should == initial_sell_in-1 }
end
context "of zero quality" do
Given(:initial_quality) { 0 }
Then { item.quality.should == 0 }
end
end
context "Aged Brie" do
Given(:name) { "Aged Brie" }
context "before sell date" do
Then { item.quality.should == initial_quality+1 }
Then { item.sell_in.should == initial_sell_in-1 }
context "with max quality" do
Given(:initial_quality) { 50 }
Then { item.quality.should == initial_quality }
Then { item.sell_in.should == initial_sell_in-1 }
end
end
context "on sell date" do
Given(:initial_sell_in) { 0 }
Then { item.quality.should == initial_quality+2 }
Then { item.sell_in.should == initial_sell_in-1 }
context "with max quality" do
Given(:initial_quality) { 50 }
Then { item.quality.should == initial_quality }
Then { item.sell_in.should == initial_sell_in-1 }
end
end
context "after sell date" do
Given(:initial_sell_in) { -10 }
Then { item.quality.should == initial_quality+2 }
Then { item.sell_in.should == initial_sell_in-1 }
context "with max quality" do
Given(:initial_quality) { 50 }
Then { item.quality.should == initial_quality }
Then { item.sell_in.should == initial_sell_in-1 }
end
end
end
context "Sulfuras" do
Given(:initial_quality) { 80 }
Given(:name) { "Sulfuras, Hand of Ragnaros" }
context "before sell date" do
Then { item.quality.should == initial_quality }
Then { item.sell_in.should == initial_sell_in }
end
context "on sell date" do
Given(:initial_sell_in) { 0 }
Then { item.quality.should == initial_quality }
Then { item.sell_in.should == initial_sell_in }
end
context "after sell date" do
Given(:initial_sell_in) { -10 }
Then { item.quality.should == initial_quality }
Then { item.sell_in.should == initial_sell_in }
end
end
context "Backstage pass" do
Given(:name) { "Backstage passes to a TAFKAL80ETC concert" }
context "long before sell date" do
Given(:initial_sell_in) { 11 }
Then { item.quality.should == initial_quality+1 }
Then { item.sell_in.should == initial_sell_in-1 }
context "at max quality" do
Given(:initial_quality) { 50 }
Then { item.quality.should == initial_quality }
end
end
context "medium close to sell date (upper bound)" do
Given(:initial_sell_in) { 10 }
Then { item.quality.should == initial_quality+2 }
Then { item.sell_in.should == initial_sell_in-1 }
context "at max quality" do
Given(:initial_quality) { 50 }
Then { item.quality.should == initial_quality }
end
end
context "medium close to sell date (lower bound)" do
Given(:initial_sell_in) { 6 }
Then { item.quality.should == initial_quality+2 }
Then { item.sell_in.should == initial_sell_in-1 }
context "at max quality" do
Given(:initial_quality) { 50 }
Then { item.quality.should == initial_quality }
end
end
context "very close to sell date (upper bound)" do
Given(:initial_sell_in) { 5 }
Then { item.quality.should == initial_quality+3 }
Then { item.sell_in.should == initial_sell_in-1 }
context "at max quality" do
Given(:initial_quality) { 50 }
Then { item.quality.should == initial_quality }
end
end
context "very close to sell date (lower bound)" do
Given(:initial_sell_in) { 1 }
Then { item.quality.should == initial_quality+3 }
Then { item.sell_in.should == initial_sell_in-1 }
context "at max quality" do
Given(:initial_quality) { 50 }
Then { item.quality.should == initial_quality }
end
end
context "on sell date" do
Given(:initial_sell_in) { 0 }
Then { item.quality.should == 0 }
Then { item.sell_in.should == initial_sell_in-1 }
end
context "after sell date" do
Given(:initial_sell_in) { -10 }
Then { item.quality.should == 0 }
Then { item.sell_in.should == initial_sell_in-1 }
end
end
context "conjured item" do
Given(:name) { "Conjured Mana Cake" }
context "before the sell date" do
Given(:initial_sell_in) { 5 }
Then { item.quality.should == initial_quality-2 }
Then { item.sell_in.should == initial_sell_in-1 }
context "at zero quality" do
Given(:initial_quality) { 0 }
Then { item.quality.should == initial_quality }
end
end
context "on sell date" do
Given(:initial_sell_in) { 0 }
Then { item.quality.should == initial_quality-2 }
Then { item.sell_in.should == initial_sell_in-1 }
context "at zero quality" do
Given(:initial_quality) { 0 }
Then { item.quality.should == initial_quality }
end
end
context "after sell date" do
Given(:initial_sell_in) { -10 }
Then { item.quality.should == initial_quality-2 }
Then { item.sell_in.should == initial_sell_in-1 }
context "at zero quality" do
Given(:initial_quality) { 0 }
Then { item.quality.should == initial_quality }
end
end
end
end
context "with several objects" do
Given(:items) {
[
Item.new("NORMAL ITEM", 5, 10),
Item.new("Aged Brie", 3, 10),
]
}
When { update_quality(items) }
Then { items[0].quality.should == 9 }
Then { items[0].sell_in.should == 4 }
Then { items[1].quality.should == 11 }
Then { items[1].sell_in.should == 2 }
end
end
task :default => :spec
task :spec do
sh "rspec ."
end
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment