Add unit tests, starting refactor

python/gilded_rose.py

@@ -5,35 +5,42 @@ class GildedRose(object):
     def __init__(self, items):
         self.items = items
 
+    def adjust_quality(self, item, rate=-1):
+        """
+        Adjust the quality of an item, defaults to -1
+        Quality cannot be less than 0 or bumped beyond 50
+        """
+        if item.quality <= 0 or item.quality >= 50:
+            return
+        item.quality += rate
+
     def update_quality(self):
         for item in self.items:
             if item.name != "Aged Brie" and item.name != "Backstage passes to a TAFKAL80ETC concert":
-                if item.quality > 0:
-                    if item.name != "Sulfuras, Hand of Ragnaros":
-                        item.quality = item.quality - 1
+                if item.name != "Sulfuras, Hand of Ragnaros":
+                    self.adjust_quality(item)
+
             else:
                 if item.quality < 50:
-                    item.quality = item.quality + 1
+                    self.adjust_quality(item, 1)
                     if item.name == "Backstage passes to a TAFKAL80ETC concert":
                         if item.sell_in < 11:
                             if item.quality < 50:
-                                item.quality = item.quality + 1
+                                self.adjust_quality(item, 1)
                         if item.sell_in < 6:
                             if item.quality < 50:
-                                item.quality = item.quality + 1
+                                self.adjust_quality(item, 1)
             if item.name != "Sulfuras, Hand of Ragnaros":
                 item.sell_in = item.sell_in - 1
             if item.sell_in < 0:
                 if item.name != "Aged Brie":
                     if item.name != "Backstage passes to a TAFKAL80ETC concert":
-                        if item.quality > 0:
-                            if item.name != "Sulfuras, Hand of Ragnaros":
-                                item.quality = item.quality - 1
+                        if item.name != "Sulfuras, Hand of Ragnaros":
+                            self.adjust_quality(item)
                     else:
-                        item.quality = item.quality - item.quality
+                        item.quality = 0
                 else:
-                    if item.quality < 50:
-                        item.quality = item.quality + 1
+                    self.adjust_quality(item, 1)
 
 
 class Item:

python/test_gilded_rose.py

@@ -5,12 +5,92 @@ from gilded_rose import Item, GildedRose
 
 
 class GildedRoseTest(unittest.TestCase):
-    def test_foo(self):
-        items = [Item("foo", 0, 0)]
+    # Once the sell by date has passed, Quality degrades twice as fast
+    def test_quality_degrades_after_sell_by_date(self):
+        items = [Item("foo", 1, 10)]
         gilded_rose = GildedRose(items)
         gilded_rose.update_quality()
-        self.assertEquals("fixme", items[0].name)
 
-        
+        self.assertEqual(0, items[0].sell_in)
+        self.assertEqual(9, items[0].quality) # Quality degraded by -1
+
+        gilded_rose.update_quality()
+        self.assertEqual(-1, items[0].sell_in)
+        self.assertEqual(7, items[0].quality) # Quality degraded by -2
+
+    # The Quality of an item is never negative
+    def test_quality_never_negative(self):
+        items = [Item("foo", 2, 0)]
+        gilded_rose = GildedRose(items)
+        gilded_rose.update_quality()
+
+        self.assertEqual(0, items[0].quality)
+
+    # "Aged Brie" actually increases in Quality the older it gets
+    def test_aged_brie_quality_increase_with_age(self):
+        items = [Item("Aged Brie", 2, 1)]
+        gilded_rose = GildedRose(items)
+        gilded_rose.update_quality()
+
+        self.assertEqual(2, items[0].quality)
+
+    # The Quality of an item is never more than 50
+    def test_quality_upper_limit(self):
+        items = [Item("Aged Brie", 2, 49)] # Using Aged Brie as quality increases
+        gilded_rose = GildedRose(items)
+        gilded_rose.update_quality()
+
+        self.assertEqual(1, items[0].sell_in)
+        self.assertEqual(50, items[0].quality)
+
+        gilded_rose.update_quality()
+        self.assertEqual(0, items[0].sell_in)
+        self.assertEqual(50, items[0].quality)
+
+    # "Sulfuras", being a legendary item, never has to be sold or decreases in Quality
+    def test_legendary_item(self):
+        items = [Item("Sulfuras, Hand of Ragnaros", 2, 80)]
+        gilded_rose = GildedRose(items)
+        gilded_rose.update_quality()
+
+        self.assertEqual(2, items[0].sell_in)
+        self.assertEqual(80, items[0].quality)
+
+
+    def test_backstage_passes(self):
+        """
+        "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
+        """
+        # Ten days or less - quality increases by 2
+        items = [Item("Backstage passes to a TAFKAL80ETC concert", 9, 10)]
+        gilded_rose = GildedRose(items)
+        gilded_rose.update_quality()
+
+        self.assertEqual(12, items[0].quality)
+
+        # Five days or less - quality increases by 3
+        items = [Item("Backstage passes to a TAFKAL80ETC concert", 3, 13)]
+        gilded_rose = GildedRose(items)
+        gilded_rose.update_quality()
+
+        self.assertEqual(16, items[0].quality)
+
+        # After the concert - quality drops to zero
+        items = [Item("Backstage passes to a TAFKAL80ETC concert", 0, 10)]
+        gilded_rose = GildedRose(items)
+        gilded_rose.update_quality()
+
+        self.assertEqual(0, items[0].quality)
+
+    # "Conjured" items degrade in Quality twice as fast as normal items
+    def test_conjured_degrade_twice_as_fast(self):
+        items = [Item("Conjured Mana Cake", 1, 5)]
+        gilded_rose = GildedRose(items)
+        gilded_rose.update_quality()
+
+        self.assertEqual(4, items[0].quality) # TODO
+
 if __name__ == '__main__':
     unittest.main()