tests working - ready to refactor;

elixir/GildedRoseRequirements.txt

@@ -0,0 +1,38 @@
+======================================
+Gilded Rose Requirements Specification
+======================================
+
+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 its 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).
+
+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.

elixir/test/gilded_rose_test.exs

@@ -1,6 +1,205 @@
 defmodule GildedRoseTest do
   use ExUnit.Case
 
-  test "begin the journey of refactoring" do
+  import GildedRose
+
+  @brie "Aged Brie"
+  @sulfuras "Sulfuras, Hand of Ragnaros"
+  @concert_ticket "Backstage passes to a TAFKAL80ETC concert"
+
+  def create_item() do
+    [
+      %Item{name: @sulfuras, sell_in: 13, quality: 1},
+      %Item{name: @concert_ticket, sell_in: 13, quality: 1},
+      %Item{name: @brie, sell_in: 13, quality: 1},
+    ]
   end
+
+  def elapse_days(items, 0), do: items
+  
+  def elapse_days(items, days) do
+    elapse_days(update_quality(items), days - 1)
+  end
+
+  test "1 day pass" do
+    result = create_item() |> elapse_days(1)
+    assert result === [
+      %Item{name: @sulfuras, sell_in: 13, quality: 1},
+      %Item{name: @concert_ticket, sell_in: 12, quality: 2},
+      %Item{name: @brie, sell_in: 12, quality: 2}
+    ]
+  end
+
+  test "2 day pass" do
+    result = create_item() |> elapse_days(2)
+    assert result === [
+      %Item{name: @sulfuras, sell_in: 13, quality: 1},
+      %Item{name: @concert_ticket, sell_in: 11, quality: 3},
+      %Item{name: @brie, sell_in: 11, quality: 3}
+    ]
+  end
+  
+  test "3 day pass" do
+    result = create_item() |> elapse_days(3)
+    assert result === [
+      %Item{name: @sulfuras, sell_in: 13, quality: 1},
+      %Item{name: @concert_ticket, sell_in: 10, quality: 4},
+      %Item{name: @brie, sell_in: 10, quality: 4}
+    ]
+  end
+
+  test "4 day pass" do
+    result = create_item() |> elapse_days(4)
+    assert result === [
+      %Item{name: @sulfuras, sell_in: 13, quality: 1},
+      %Item{name: @concert_ticket, sell_in: 9, quality: 6}, # Here the tickets start increasing by 2
+      %Item{name: @brie, sell_in: 9, quality: 5}            
+    ]
+  end
+
+  test "5 day pass" do
+    result = create_item() |> elapse_days(5)
+    assert result === [
+      %Item{name: @sulfuras, sell_in: 13, quality: 1},
+      %Item{name: @concert_ticket, sell_in: 8, quality: 8},
+      %Item{name: @brie, sell_in: 8, quality: 6}
+    ]         
+  end
+  
+
+  test "6 day pass" do
+    result = create_item() |> elapse_days(6)
+    assert result === [
+      %Item{name: @sulfuras, sell_in: 13, quality: 1},
+      %Item{name: @concert_ticket, sell_in: 7, quality: 10},
+      %Item{name: @brie, sell_in: 7, quality: 7}
+    ]      
+  end
+
+  test "7 day pass" do
+    result = create_item() |> elapse_days(7)
+    assert result === [
+      %Item{name: @sulfuras, sell_in: 13, quality: 1},
+      %Item{name: @concert_ticket, sell_in: 6, quality: 12},
+      %Item{name: @brie, sell_in: 6, quality: 8}
+    ]
+  end
+
+  test "8 day pass" do
+    result = create_item() |> elapse_days(8)
+    assert result === [
+      %Item{name: @sulfuras, sell_in: 13, quality: 1},
+      %Item{name: @concert_ticket, sell_in: 5, quality: 14},
+      %Item{name: @brie, sell_in: 5, quality: 9}
+    ]
+  end
+
+  test "9 day pass" do
+    result = create_item() |> elapse_days(9)
+    assert result === [
+      %Item{name: @sulfuras, sell_in: 13, quality: 1},
+      %Item{name: @concert_ticket, sell_in: 4, quality: 17},
+      %Item{name: @brie, sell_in: 4, quality: 10}
+    ]
+  end
+
+  test "10 day pass" do
+    result = create_item() |> elapse_days(10)
+    assert result === [
+      %Item{name: @sulfuras, sell_in: 13, quality: 1},
+      %Item{name: @concert_ticket, sell_in: 3, quality: 20},
+      %Item{name: @brie, sell_in: 3, quality: 11}
+    ]
+  end
+
+  test "11 day pass" do
+    result = create_item() |> elapse_days(11)
+    assert result === [
+      %Item{name: @sulfuras, sell_in: 13, quality: 1},
+      %Item{name: @concert_ticket, sell_in: 2, quality: 23},
+      %Item{name: @brie, sell_in: 2, quality: 12}
+    ]
+  end
+
+  test "12 day pass" do
+    result = create_item() |> elapse_days(12)
+    assert result === [
+      %Item{name: @sulfuras, sell_in: 13, quality: 1},
+      %Item{name: @concert_ticket, sell_in: 1, quality: 26},
+      %Item{name: @brie, sell_in: 1, quality: 13}
+    ]
+  end
+
+  test "13 day pass" do
+    result = create_item() |> elapse_days(13)
+    assert result === [
+      %Item{name: @sulfuras, sell_in: 13, quality: 1},
+      %Item{name: @concert_ticket, sell_in: 0, quality: 29},
+      %Item{name: @brie, sell_in: 0, quality: 14}
+    ]
+  end
+
+  test "14 day pass" do
+    result = create_item() |> elapse_days(14)
+    assert result === [
+      %Item{name: @sulfuras, sell_in: 13, quality: 1},
+      %Item{name: @concert_ticket, sell_in: -1, quality: 0},
+      %Item{name: @brie, sell_in: -1, quality: 16}            # After days are over brie quality doubles
+    ]
+  end
+
+  test "15 day pass" do
+    result = create_item() |> elapse_days(15)
+    assert result === [
+      %Item{name: @sulfuras, sell_in: 13, quality: 1},
+      %Item{name: @concert_ticket, sell_in: -2, quality: 0},
+      %Item{name: @brie, sell_in: -2, quality: 18},
+    ]
+  end
+
+  test "16 day pass" do
+    result = create_item() |> elapse_days(16)
+    assert result === [
+      %Item{name: @sulfuras, sell_in: 13, quality: 1},
+      %Item{name: @concert_ticket, sell_in: -3, quality: 0},
+      %Item{name: @brie, sell_in: -3, quality: 20},
+    ]
+  end
+
+  test "17 day pass" do
+    result = create_item() |> elapse_days(17)
+    assert result === [
+      %Item{name: @sulfuras, sell_in: 13, quality: 1},
+      %Item{name: @concert_ticket, sell_in: -4, quality: 0},
+      %Item{name: @brie, sell_in: -4, quality: 22},
+    ]
+  end
+
+  test "18 day pass" do
+    result = create_item() |> elapse_days(18)
+    assert result === [
+      %Item{name: @sulfuras, sell_in: 13, quality: 1},
+      %Item{name: @concert_ticket, sell_in: -5, quality: 0},
+      %Item{name: @brie, sell_in: -5, quality: 24},
+    ]
+  end
+
+  test "19 day pass" do
+    result = create_item() |> elapse_days(19)
+    assert result === [
+      %Item{name: @sulfuras, sell_in: 13, quality: 1},
+      %Item{name: @concert_ticket, sell_in: -6, quality: 0},
+      %Item{name: @brie, sell_in: -6, quality: 26},
+    ]
+  end
+
+  test "20 day pass" do
+    result = create_item() |> elapse_days(20)
+    assert result === [
+      %Item{name: @sulfuras, sell_in: 13, quality: 1},
+      %Item{name: @concert_ticket, sell_in: -7, quality: 0},  
+      %Item{name: @brie, sell_in: -7, quality: 28},
+    ]
+  end
+
 end