Cover the existing use cases with comprehensive tests

ruby/gilded_rose_spec.rb

@@ -1,12 +1,126 @@
 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"
+      expect(items[0].name).to eq "foo"
+    end
+
+    it 'ages regular items correctly when sell_in exceeds quality' do
+      items = [Item.new("foo", 4, 2)]
+      updater = GildedRose.new(items)
+      updater.update_quality()
+
+      expect(items[0].sell_in).to eq 3
+      expect(items[0].quality).to eq 1
+
+      2.times do
+        updater.update_quality()
+      end
+
+      expect(items[0].sell_in).to eq 1
+      expect(items[0].quality).to eq 0 # does not go below zero
+
+      3.times do
+        updater.update_quality()
+      end
+
+      expect(items[0].sell_in).to eq -2 # does go below zero
+      expect(items[0].quality).to eq 0 # does not go below zero
+    end
+
+    it 'ages regular items correctly when quality exceeds sell_in' do
+      items = [Item.new("foo", 2, 8)]
+      updater = GildedRose.new(items)
+      2.times do
+        updater.update_quality()
+      end
+
+      expect(items[0].sell_in).to eq 0
+      expect(items[0].quality).to eq 6 # drops 1 quality per call when sell_in >= zero
+
+      2.times do
+        updater.update_quality()
+      end
+
+      expect(items[0].sell_in).to eq -2
+      expect(items[0].quality).to eq 2 # drops 2 quality per call when sell_in < zero
+
+      2.times do
+        updater.update_quality()
+      end
+
+      expect(items[0].sell_in).to eq -4
+      expect(items[0].quality).to eq 0 # does not go below zero
+    end
+
+    it 'ages brie' do
+      items = [Item.new("Aged Brie", 1, 46)]
+      updater = GildedRose.new(items)
+      updater.update_quality()
+
+      expect(items[0].sell_in).to eq 0
+      expect(items[0].quality).to eq 47 # increases 1 quality per call when sell_in >= zero
+
+      updater.update_quality()
+
+      expect(items[0].sell_in).to eq -1
+      expect(items[0].quality).to eq 49 # increases 2 quality per call when sell_in < zero
+
+      2.times do
+        updater.update_quality()
+      end
+
+      expect(items[0].sell_in).to eq -3
+      expect(items[0].quality).to eq 50 # does not exceed 50
+    end
+
+    it "ages concert tickets" do
+      items = [Item.new("Backstage passes to a TAFKAL80ETC concert", 11, 29)]
+      updater = GildedRose.new(items)
+      updater.update_quality()
+
+      expect(items[0].sell_in).to eq 10
+      expect(items[0].quality).to eq 30 # increases 1 quality per call when sell_in > 10
+
+      5.times do
+        updater.update_quality()
+      end
+
+      expect(items[0].sell_in).to eq 5
+      expect(items[0].quality).to eq 40 # incrases 2 quality per call when sell_in is (6..10)
+
+      3.times do
+        updater.update_quality()
+      end
+
+      expect(items[0].sell_in).to eq 2
+      expect(items[0].quality).to eq 49 # incrases 3 quality per call when sell_in is (6..10)
+
+      2.times do
+        updater.update_quality()
+      end
+
+      expect(items[0].sell_in).to eq 0
+      expect(items[0].quality).to eq 50 # does not exceed 50
+
+      updater.update_quality()
+
+      expect(items[0].sell_in).to eq -1
+      expect(items[0].quality).to eq 0 # too slow, now they are worth nothing!
+    end
+
+    it "seems Sulfuras would find the gilded lily to be a... second hand shop" do
+      items = [Item.new("Sulfuras, Hand of Ragnaros", 1, 80)]
+      updater = GildedRose.new(items)
+      2.times do
+        updater.update_quality()
+      end
+
+      expect(items[0].sell_in).to eq 1 # does not change
+      expect(items[0].quality).to eq 80 # always 80
     end
   end