Add conjuring

Signed-off-by: Jean-Maxime <jm.fillau@gmail.com>

python/gilded_rose.py

@@ -85,3 +85,15 @@ class BackstagePassUpdater(ItemUpdater):
             self.item.quality = min(50, self.item.quality + 1)  # More than 10 days: +1
 
         self.item.sell_in = self.item.sell_in - 1
+
+@ItemUpdater.register("Conjured")
+class ConjuredItemUpdater(ItemUpdater):
+
+    def update(self):
+        self.item.sell_in = self.item.sell_in - 1
+
+        if self.item.quality > 0:
+            self.item.quality = self.item.quality - 2
+
+        if self.item.sell_in < 0 and self.item.quality > 0:
+            self.item.quality = self.item.quality - 2

python/tests/test_gilded_rose.py

@@ -101,5 +101,28 @@ class GildedRoseBackstagePassTest(unittest.TestCase):
         self.assertEqual(0, items[0].quality)
         self.assertEqual(-1, items[0].sell_in)
 
+class GildedRoseConjuredItemTest(unittest.TestCase):
+
+    def test_item_quality(self):
+        items = [Item("Conjured", 20, 40)]
+        gilded_rose = GildedRose(items)
+        gilded_rose.update_quality()
+        self.assertEqual(38, items[0].quality)
+        self.assertEqual(19, items[0].sell_in)
+
+    def test_item_quality_sell_in_passed(self):
+        items = [Item("Conjured", 0, 40)]
+        gilded_rose = GildedRose(items)
+        gilded_rose.update_quality()
+        self.assertEqual(36, items[0].quality)
+        self.assertEqual(-1, items[0].sell_in)
+
+    def test_item_quality_sell_can_be_negative(self):
+        items = [Item("Conjured", 20, 0)]
+        gilded_rose = GildedRose(items)
+        gilded_rose.update_quality()
+        self.assertEqual(0, items[0].quality)
+        self.assertEqual(19, items[0].sell_in)
+
 if __name__ == '__main__':
     unittest.main()