4.2: enforce quality validation with tests

- Implement quality bounds checking on initialization
- Add special handling for legendary items
- Include comprehensive test coverage

python/gilded_rose.py

@@ -16,7 +16,16 @@ class GildedRose(object):
 
     def __init__(self, items):
         self.items = items
+        self.items = items
+        for item in items:
+            self._enforce_quality_bounds(item)
 
+    def _enforce_quality_bounds(self, item):
+        if item.name == self.LEGENDARY_ITEM:
+            if item.quality != self.LEGENDARY_QUALITY:
+                item.quality = self.LEGENDARY_QUALITY  # Enforce legendary quality
+        else:
+            item.quality = max(0, min(self.MAX_QUALITY, item.quality))
 
     def update_quality(self):
         for item in self.items:
@@ -32,7 +41,7 @@ class GildedRose(object):
             self.update_backstage_pass(item)
         elif ITEM_NAME.CONJURED in item.name:
             self.update_conjured_item(item)
-        elif item.name != ITEM_NAME.SULFURAS:
+        elif item.name != self.LEGENDARY_ITEM:
             self.update_normal_item(item)
 
     def update_conjured_item(self, item):
@@ -40,7 +49,7 @@ class GildedRose(object):
         self.decrease_quality(item)
 
     def update_sell_in(self, item):
-        if item.name != ITEM_NAME.SULFURAS:
+        if item.name != self.LEGENDARY_ITEM:
             item.sell_in -= 1
 
     def handle_expired_item(self, item):
@@ -51,7 +60,7 @@ class GildedRose(object):
         elif ITEM_NAME.CONJURED in item.name:
             self.decrease_quality(item)
             self.decrease_quality(item)
-        elif item.name != ITEM_NAME.SULFURAS:
+        elif item.name != self.LEGENDARY_ITEM:
             self.decrease_quality(item)
 
     def update_aged_brie(self, item):

python/test_gilded_rose.py

@@ -107,6 +107,7 @@ class GildedRoseTest(unittest.TestCase):
         gilded_rose.update_quality()
         self.assertEqual("foo", items[0].name)
 
+    # Conjured Items
     def test_conjured_item_quality_decreases_twice_as_fast(self):
         items = [Item("Conjured Mana Cake", 10, 20)]
         gilded_rose = GildedRose(items)
@@ -125,6 +126,55 @@ class GildedRoseTest(unittest.TestCase):
         gilded_rose.update_quality()
         self.assertEqual(0, items[0].quality)
 
+    # Add these test cases to enforce quality bounds
+
+    def test_legendary_item_quality_enforced_on_creation(self):
+        """Test that Sulfuras quality is automatically set to 80 if initialized with wrong value"""
+        items = [Item("Sulfuras, Hand of Ragnaros", 5, 50)]  # Incorrect quality
+        gilded_rose = GildedRose(items)
+        self.assertEqual(80, items[0].quality)  # Should be corrected to 80
+
+    def test_normal_item_quality_clamped_on_creation(self):
+        """Test that normal items' quality is clamped to 0-50 range during initialization"""
+        items = [Item("Normal Item", 5, 60)]  # Above max
+        gilded_rose = GildedRose(items)
+        self.assertEqual(50, items[0].quality)
+
+        items = [Item("Normal Item", 5, -5)]  # Below min
+        gilded_rose = GildedRose(items)
+        self.assertEqual(0, items[0].quality)
+
+    def test_legendary_item_quality_unchanged_by_updates(self):
+        """Test that Sulfuras quality remains 80 even after multiple updates"""
+        items = [Item("Sulfuras, Hand of Ragnaros", 5, 80)]
+        gilded_rose = GildedRose(items)
+        for _ in range(5):  # Multiple updates
+            gilded_rose.update_quality()
+        self.assertEqual(80, items[0].quality)
+        self.assertEqual(5, items[0].sell_in)  # Sell_in should not change
+
+    def test_backstage_pass_quality_clamped_on_creation(self):
+        """Test that backstage pass quality is clamped to 0-50 during initialization"""
+        items = [Item("Backstage passes to a TAFKAL80ETC concert", 15, 60)]
+        gilded_rose = GildedRose(items)
+        self.assertEqual(50, items[0].quality)
+
+    def test_conjured_item_quality_clamped_on_creation(self):
+        """Test that conjured items' quality is clamped to 0-50 during initialization"""
+        items = [Item("Conjured Mana Cake", 5, 60)]
+        gilded_rose = GildedRose(items)
+        self.assertEqual(50, items[0].quality)
+
+        items = [Item("Conjured Mana Cake", 5, -10)]
+        gilded_rose = GildedRose(items)
+        self.assertEqual(0, items[0].quality)
+
+    def test_aged_brie_quality_clamped_on_creation(self):
+        """Test that Aged Brie quality is clamped to 0-50 during initialization"""
+        items = [Item("Aged Brie", 5, 60)]
+        gilded_rose = GildedRose(items)
+        self.assertEqual(50, items[0].quality)
+