feat: python kata

python/gilded_rose.py

@@ -1,41 +1,5 @@
 # -*- coding: utf-8 -*-
 
-class GildedRose(object):
-
-    def __init__(self, items):
-        self.items = items
-
-    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
-            else:
-                if item.quality < 50:
-                    item.quality = item.quality + 1
-                    if item.name == "Backstage passes to a TAFKAL80ETC concert":
-                        if item.sell_in < 11:
-                            if item.quality < 50:
-                                item.quality = item.quality + 1
-                        if item.sell_in < 6:
-                            if item.quality < 50:
-                                item.quality = item.quality + 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
-                    else:
-                        item.quality = item.quality - item.quality
-                else:
-                    if item.quality < 50:
-                        item.quality = item.quality + 1
-
-
 class Item:
     def __init__(self, name, sell_in, quality):
         self.name = name
@@ -44,3 +8,88 @@ class Item:
 
     def __repr__(self):
         return "%s, %s, %s" % (self.name, self.sell_in, self.quality)
+
+
+class BaseRule:
+    def __init__(self, degrade_rate: int = -1) -> None:
+        self.degrade_rate = degrade_rate
+
+    def _calculate_quality_diff(self, item: Item) -> int:
+        sell_date_multiplier = 1 + int(item.sell_in < 0)
+        return self.degrade_rate * sell_date_multiplier
+
+    def update_quality(self, item: Item) -> None:
+        calculated_new_quality = item.quality + self._calculate_quality_diff(item)
+        # The quality of an item is never more than 50 and is never less than 0
+        item.quality = min(50, max(0, calculated_new_quality))
+
+
+class IncreasingQualityRule(BaseRule):
+    def __init__(self) -> None:
+        super().__init__(1)
+
+
+class SulfurasRule(BaseRule):
+    def update_quality(self, item: Item) -> None:
+        # "Sulfuras", being a legendary item, never has to be sold or decreases in Quality
+        item.quality = 80
+
+
+class BackstageRule(IncreasingQualityRule):
+    def _calculate_quality_diff(self, item: Item) -> int:
+        # If there are more than 10 days until the concert, same rules as parent class apply
+        if item.sell_in > 10:
+            return super()._calculate_quality_diff(item)
+        # If there are 10 or fewer days until the concert, but more than 5, degrade_rate = 2
+        if item.sell_in > 5:
+            return 2
+        # If there are 5 or fewer days until the concert, degrade_rate = 2
+        return 3
+
+    def update_quality(self, item: Item) -> None:
+        # Tickets are useless when the concert is in the past
+        if item.sell_in < 0:
+            item.quality = 0
+            return
+        super().update_quality(item)
+
+
+class ConjuredRule(BaseRule):
+    def __init__(self):
+        super().__init__(-2)
+
+
+class RuleProvider:
+    def __init__(self):
+        self.base_rule = BaseRule()
+        self.increasing_quality_rule = IncreasingQualityRule()
+        self.sulfuras_rule = SulfurasRule()
+        self.backstage_rule = BackstageRule()
+        self.conjured_rule = ConjuredRule()
+
+    def get_rule_for_item_name(self, name: str) -> BaseRule:
+        if name.lower().startswith('sulfuras'):
+            return self.sulfuras_rule
+        if name.lower().startswith('aged'):
+            return self.increasing_quality_rule
+        if name.lower().startswith('backstage'):
+            return self.backstage_rule
+        if name.lower().startswith('conjured'):
+            return self.conjured_rule
+        return self.base_rule
+
+
+class GildedRose(object):
+    def __init__(self, items: list[Item]) -> None:
+        self.items = items
+        self.rule_provider = RuleProvider()
+
+    def update_quality_over_range(self, update_range: int) -> None:
+        for _ in range(update_range): self.update_quality()
+
+    def update_quality(self) -> None:
+        self.advance_day()
+        for item in self.items: self.rule_provider.get_rule_for_item_name(item.name).update_quality(item)
+
+    def advance_day(self) -> None:
+        for item in self.items: item.sell_in -= 1

python/test_gilded_rose.py

@@ -5,12 +5,52 @@ from gilded_rose import Item, GildedRose
 
 
 class GildedRoseTest(unittest.TestCase):
-    def test_foo(self):
-        items = [Item("foo", 0, 0)]
+    def test_base_rule(self):
+        items = [Item('+5 Dexterity Vest', 16, 50)]
         gilded_rose = GildedRose(items)
         gilded_rose.update_quality()
-        self.assertEqual("fixme", items[0].name)
+        self.assertEqual(15, items[0].sell_in)
+        self.assertEqual(49, items[0].quality)
+
+        gilded_rose.update_quality_over_range(15)
+        self.assertEqual(0, items[0].sell_in)
+        self.assertEqual(34, items[0].quality)
+
+        gilded_rose.update_quality()
+        self.assertEqual(15, items[0].sell_in)
+        self.assertEqual(49, items[0].quality)
+
+    def test_backstage_rule(self):
+        items = [Item('Backstage passes to a TAFKAL80ETC concert', 16, 0)]
+        gilded_rose = GildedRose(items)
+        gilded_rose.update_quality()
+        self.assertEqual(15, items[0].sell_in)
+        self.assertEqual(1, items[0].quality)
+
+        gilded_rose.update_quality_over_range(4)
+        self.assertEqual(11, items[0].sell_in)
+        self.assertEqual(5, items[0].quality)
+
+        gilded_rose.update_quality()
+        self.assertEqual(10, items[0].sell_in)
+        self.assertEqual(7, items[0].quality)
+
+        gilded_rose.update_quality_over_range(4)
+        self.assertEqual(6, items[0].sell_in)
+        self.assertEqual(15, items[0].quality)
+
+        gilded_rose.update_quality()
+        self.assertEqual(5, items[0].sell_in)
+        self.assertEqual(18, items[0].quality)
+
+        gilded_rose.update_quality_over_range(5)
+        self.assertEqual(0, items[0].sell_in)
+        self.assertEqual(33, items[0].quality)
+
+        gilded_rose.update_quality()
+        self.assertEqual(-1, items[0].sell_in)
+        self.assertEqual(0, items[0].quality)
+
 
-        
 if __name__ == '__main__':
     unittest.main()