Write tests for all types of items

Without looking at the code I've written specs based on the requirements listed and the output of the texttest.
All specs are green except for the expected 2 failing 'quality' tests for the new 'Conjured' item.
With all models tested I feel more comfortable starting the refactor. The plan at the moment is to extract the code of 1 type of item at the time into it's own method.

ruby/gilded_rose_spec.rb

@@ -1,13 +0,0 @@
-require File.join(File.dirname(__FILE__), 'gilded_rose')
-
-describe GildedRose do
-
-  describe "#update_quality" do
-    it "does not change the name" do
-      items = [Item.new("foo", 0, 0)]
-      GildedRose.new(items).update_quality()
-      expect(items[0].name).to eq "fixme"
-    end
-  end
-
-end

ruby/gilded_rose_tests.rb

@@ -1,12 +0,0 @@
-require File.join(File.dirname(__FILE__), 'gilded_rose')
-require 'test/unit'
-
-class TestUntitled < Test::Unit::TestCase
-
-  def test_foo
-    items = [Item.new("foo", 0, 0)]
-    GildedRose.new(items).update_quality()
-    assert_equal items[0].name, "fixme"
-  end
-
-end

ruby/specs/gilded_rose_spec.rb

@@ -0,0 +1,204 @@
+require_relative '../gilded_rose'
+
+describe GildedRose do
+  let(:quality) { 3 }
+  let(:sell_in) { 3 }
+  let(:item_name) { 'Elixir of the Mongoose' }
+  let(:item) { Item.new(item_name, sell_in, quality) }
+  let(:items) { [item] }
+
+  subject { GildedRose.new(items) }
+
+  describe '#update_quality' do
+    context "when item is regular like e.g. 'Elixir of the Mongoose'" do
+      context 'when sell by date has not passed' do
+        it 'lowers quality by 1' do
+          subject.update_quality
+          expect(items[0].quality).to eq 2
+        end
+
+        it 'lowers sell_in by 1' do
+          subject.update_quality
+          expect(items[0].sell_in).to eq 2
+        end
+      end
+
+      context 'when sell by date has passed' do
+        let(:sell_in) { 0 }
+
+        it 'lowers quality by 2' do
+          subject.update_quality
+          expect(items[0].quality).to eq 1
+        end
+
+        it 'lowers sell_in by 1' do
+          subject.update_quality
+          expect(items[0].sell_in).to eq -1
+        end
+      end
+
+      it 'does never lower the quality below 0' do
+        items = [Item.new(item_name, sell_in, 0)]
+        subject.update_quality
+        expect(items[0].quality).to eq 0
+      end
+    end
+
+    context "when item name is 'Sulfuras, Hand of Ragnaros'" do
+      let(:item_name) { 'Sulfuras, Hand of Ragnaros' }
+      let(:quality) { 80 }
+
+      context 'when sell by date has not passed' do
+        it 'does not lower quality by 1' do
+          subject.update_quality
+          expect(items[0].quality).to eq 80
+        end
+
+        it 'does not lower sell_in' do
+          subject.update_quality
+          expect(items[0].sell_in).to eq 3
+        end
+      end
+
+      context 'when sell by date has passed' do
+        let(:sell_in) { 0 }
+
+        it 'does not lower quality by 1' do
+          subject.update_quality
+          expect(items[0].quality).to eq 80
+        end
+
+        it 'does not lower sell_in' do
+          subject.update_quality
+          expect(items[0].sell_in).to eq 0
+        end
+      end
+    end
+
+    context "when item name is 'Aged Brie'" do
+      let(:item_name) { 'Aged Brie' }
+
+      context 'when sell by date has not passed' do
+        it 'increases quality by 1' do
+          subject.update_quality
+          expect(items[0].quality).to eq 4
+        end
+
+        it 'lowers sell_in by 1' do
+          subject.update_quality
+          expect(items[0].sell_in).to eq 2
+        end
+      end
+
+      context 'when sell by date has passed' do
+        let(:sell_in) { 0 }
+
+        it 'increases quality by 2' do
+          subject.update_quality
+          expect(items[0].quality).to eq 5
+        end
+
+        it 'lowers sell_in by 1' do
+          subject.update_quality
+          expect(items[0].sell_in).to eq -1
+        end
+      end
+
+      it 'does never raise the quality above 50' do
+        items = [Item.new(item_name, sell_in, 50)]
+        subject.update_quality
+        expect(items[0].quality).to eq 50
+      end
+    end
+
+    context "when item name is 'Backstage passes to a TAFKAL80ETC concert'" do
+      let(:item_name) { 'Backstage passes to a TAFKAL80ETC concert' }
+
+      context 'when sell by date has not passed' do
+        context 'when 10 or less days remaining' do
+          let(:sell_in) { 10 }
+
+          it 'increases quality by 2' do
+            subject.update_quality
+            expect(items[0].quality).to eq 5
+          end
+
+          it 'lowers sell_in by 1' do
+            subject.update_quality
+            expect(items[0].sell_in).to eq 9
+          end
+        end
+
+        context 'when 5 or less days remaining' do
+          let(:sell_in) { 5 }
+          it 'increases quality by 3' do
+            subject.update_quality
+            expect(items[0].quality).to eq 6
+          end
+
+          it 'lowers sell_in by 1' do
+            subject.update_quality
+            expect(items[0].sell_in).to eq 4
+          end
+        end
+      end
+
+      context 'when sell by date has passed' do
+        let(:sell_in) { 0 }
+
+        it 'increases quality by 2' do
+          subject.update_quality
+          expect(items[0].quality).to eq 0
+        end
+
+        it 'lowers sell_in by 1' do
+          subject.update_quality
+          expect(items[0].sell_in).to eq -1
+        end
+      end
+
+      it 'does never raise the quality above 50' do
+        items = [Item.new(item_name, sell_in, 50)]
+        subject.update_quality
+        expect(items[0].quality).to eq 50
+      end
+    end
+
+    xcontext "when item name is 'Conjured Mana Cake'" do
+      let(:item_name) { 'Conjured Mana Cake' }
+
+      context 'when sell by date has not passed' do
+        it 'lowers quality by 2' do
+          subject.update_quality
+          expect(items[0].quality).to eq 1
+        end
+
+        it 'lowers sell_in by 1' do
+          subject.update_quality
+          expect(items[0].sell_in).to eq 2
+        end
+      end
+
+      context 'when sell by date has passed' do
+        let(:sell_in) { 0 }
+        let(:quality) { 6 }
+
+        it 'lowers quality by 4' do
+          subject.update_quality
+          expect(items[0].quality).to eq 2
+        end
+
+        it 'lowers sell_in by 1' do
+          subject.update_quality
+          expect(items[0].sell_in).to eq -1
+        end
+      end
+
+      it 'does never lower the quality below 0' do
+        items = [Item.new(item_name, sell_in, 0)]
+        subject.update_quality
+        expect(items[0].quality).to eq 0
+      end
+    end
+  end
+end