test: add test case scenarios

python/tests/test_aged_brie.py

@@ -0,0 +1,39 @@
+import pytest
+
+from gilded_rose import Item, AgedBrie
+
+
+def test_aged_brie_increases_quality_by_1_before_sell_date():
+    # constructing via Item maps to AgedBrie automatically
+    item = Item("Aged Brie", sell_in=10, quality=10)
+    item.daily_step()
+    assert isinstance(item, AgedBrie)
+    assert item.sell_in == 9
+    assert item.quality == 11
+
+
+def test_aged_brie_increases_quality_by_2_after_sell_date():
+    item = Item("Aged Brie", sell_in=0, quality=10)
+    item.daily_step()
+    assert item.sell_in == -1
+    assert item.quality == 12
+
+
+def test_aged_brie_quality_capped_at_50():
+    item = Item("Aged Brie", sell_in=5, quality=49)
+    item.daily_step()
+    assert item.quality == 50
+    item.daily_step()
+    assert item.quality == 50
+
+
+def test_aged_brie_stays_at_50_if_already_max():
+    item = Item("Aged Brie", sell_in=5, quality=50)
+    item.daily_step()
+    assert item.quality == 50
+
+
+def test_aged_brie_init_over_50_raises():
+    with pytest.raises(AssertionError):
+        # AgedBrie inherits Item constraints: must be <= 50
+        Item("Aged Brie", sell_in=5, quality=51)

python/tests/test_backstage_passes.py

@@ -0,0 +1,39 @@
+import pytest
+
+from gilded_rose import Item, BackstagePasses
+
+
+def test_backstage_passes_increase_by_1_when_more_than_10_days():
+    item = Item("Backstage passes to a TAFKAL80ETC concert", sell_in=15, quality=10)
+    item.daily_step()
+    assert isinstance(item, BackstagePasses)
+    assert item.sell_in == 14
+    assert item.quality == 11
+
+
+def test_backstage_passes_increase_by_2_between_10_and_6_days():
+    item = Item("Backstage passes to a TAFKAL80ETC concert", sell_in=10, quality=10)
+    item.daily_step()
+    assert item.sell_in == 9
+    assert item.quality == 12
+
+
+def test_backstage_passes_increase_by_3_between_5_and_1_days():
+    item = Item("Backstage passes to a TAFKAL80ETC concert", sell_in=5, quality=10)
+    item.daily_step()
+    assert item.sell_in == 4
+    assert item.quality == 13
+
+
+def test_backstage_passes_drop_to_zero_after_concert():
+    item = Item("Backstage passes to a TAFKAL80ETC concert", sell_in=0, quality=40)
+    item.daily_step()
+    assert item.sell_in == -1
+    assert item.quality == 0
+
+
+def test_backstage_passes_quality_capped_at_50():
+    # At 5 days, would add +3 but must cap at 50
+    item = Item("Backstage passes to a TAFKAL80ETC concert", sell_in=5, quality=49)
+    item.daily_step()
+    assert item.quality == 50

python/tests/test_conjured.py

@@ -0,0 +1,35 @@
+import pytest
+
+from gilded_rose import Item, Conjured
+
+
+def test_conjured_degrades_by_2_before_sell_date():
+    item = Item("Conjured Mana Cake", sell_in=3, quality=10)
+    item.daily_step()
+    assert isinstance(item, Conjured)
+    assert item.sell_in == 2
+    assert item.quality == 8
+
+
+def test_conjured_degrades_by_4_after_sell_date():
+    item = Item("Conjured Mana Cake", sell_in=0, quality=10)
+    item.daily_step()
+    assert item.sell_in == -1
+    assert item.quality == 6
+
+
+def test_conjured_never_negative():
+    item = Item("Conjured Mana Cake", sell_in=0, quality=3)
+    item.daily_step()
+    assert item.quality == 0
+
+
+def test_conjured_sell_in_decrements():
+    item = Item("Conjured Mana Cake", sell_in=5, quality=10)
+    item.daily_step()
+    assert item.sell_in == 4
+
+
+def test_conjured_mapping_via_item_new():
+    item = Item("Conjured Mana Cake", sell_in=5, quality=10)
+    assert isinstance(item, Conjured)

python/tests/test_gilded_rose.py

@@ -9,7 +9,7 @@ class GildedRoseTest(unittest.TestCase):
         items = [Item("foo", 0, 0)]
         gilded_rose = GildedRose(items)
         gilded_rose.update_quality()
-        self.assertEqual("fixme", items[0].name)
+        self.assertEqual("foo", items[0].name)
 
         
 if __name__ == '__main__':

python/tests/test_gilded_rose_integration.py

@@ -0,0 +1,64 @@
+from gilded_rose import Item, GildedRose, AgedBrie, BackstagePasses, Sulfuras, Conjured
+
+
+def test_gilded_rose_updates_normal_item():
+    items = [Item("Normal", sell_in=2, quality=5)]
+    gr = GildedRose(items)
+    gr.update_quality()
+    assert items[0].sell_in == 1
+    assert items[0].quality == 4
+
+
+def test_gilded_rose_updates_aged_brie():
+    items = [Item("Aged Brie", sell_in=2, quality=0)]
+    gr = GildedRose(items)
+    gr.update_quality()
+    assert isinstance(items[0], AgedBrie)
+    assert items[0].sell_in == 1
+    assert items[0].quality == 1
+
+
+def test_gilded_rose_updates_backstage_passes_near_concert():
+    items = [Item("Backstage passes to a TAFKAL80ETC concert", sell_in=5, quality=10)]
+    gr = GildedRose(items)
+    gr.update_quality()
+    assert isinstance(items[0], BackstagePasses)
+    assert items[0].sell_in == 4
+    assert items[0].quality == 13
+
+
+def test_gilded_rose_keeps_sulfuras_constant():
+    items = [Item("Sulfuras, Hand of Ragnaros", sell_in=10, quality=80)]
+    gr = GildedRose(items)
+    gr.update_quality()
+    assert isinstance(items[0], Sulfuras)
+    assert items[0].sell_in == 0
+    assert items[0].quality == 80
+
+
+def test_gilded_rose_updates_mixed_items():
+    items = [
+        Item("Normal", sell_in=1, quality=2),
+        Item("Aged Brie", sell_in=1, quality=49),
+        Item("Backstage passes to a TAFKAL80ETC concert", sell_in=10, quality=48),
+        Item("Conjured Mana Cake", sell_in=3, quality=6),
+        Item("Sulfuras, Hand of Ragnaros", sell_in=0, quality=80),
+    ]
+    gr = GildedRose(items)
+    gr.update_quality()
+
+    # Normal
+    assert items[0].sell_in == 0 and items[0].quality == 1
+
+    # Aged Brie capped at 50
+    assert items[1].sell_in == 0 and items[1].quality == 50
+
+    # Backstage +2 at 10 days, capped at 50
+    assert items[2].sell_in == 9 and items[2].quality == 50
+
+    # Conjured -2
+    assert isinstance(items[3], Conjured)
+    assert items[3].sell_in == 2 and items[3].quality == 4
+
+    # Sulfuras constant
+    assert items[4].sell_in == 0 and items[4].quality == 80

python/tests/test_item.py

@@ -0,0 +1,37 @@
+import pytest
+
+from gilded_rose import Item
+
+
+def test_item_decreases_quality_and_sell_in():
+    item = Item("foo", sell_in=10, quality=20)
+    item.daily_step()
+    assert item.sell_in == 9
+    assert item.quality == 19
+
+
+def test_item_quality_never_negative():
+    item = Item("bar", sell_in=5, quality=0)
+    item.daily_step()
+    assert item.quality == 0
+
+
+def test_item_degrades_twice_as_fast_after_sell_date():
+    item = Item("baz", sell_in=0, quality=10)
+    # After sell-in passes, degradation doubles
+    item.daily_step()
+    assert item.sell_in == -1
+    assert item.quality == 8
+
+
+def test_item_quality_floor_boundary():
+    item = Item("qux", sell_in=1, quality=1)
+    item.daily_step()
+    assert item.quality == 0
+    item.daily_step()  # now past sell date, but cannot drop below 0
+    assert item.quality == 0
+
+
+def test_item_init_with_negative_quality_raises():
+    with pytest.raises(AssertionError):
+        Item("oops", sell_in=5, quality=-1)

python/tests/test_sulfuras.py

@@ -0,0 +1,37 @@
+import pytest
+
+from gilded_rose import Item, Sulfuras
+
+
+def test_sulfuras_is_immutable_over_time():
+    item = Item("Sulfuras, Hand of Ragnaros", sell_in=5, quality=80)
+    item.daily_step()
+    assert isinstance(item, Sulfuras)
+    assert item.sell_in == 0  # forced to 0 in constructor
+    assert item.quality == 80
+
+
+def test_sulfuras_constructor_forces_quality_and_sell_in():
+    item = Item("Sulfuras, Hand of Ragnaros", sell_in=999, quality=10)
+    assert item.sell_in == 0
+    assert item.quality == 80
+
+
+def test_sulfuras_multiple_days_unchanged():
+    item = Item("Sulfuras, Hand of Ragnaros", sell_in=0, quality=80)
+    for _ in range(10):
+        item.daily_step()
+    assert item.sell_in == 0
+    assert item.quality == 80
+
+
+def test_sulfuras_mapping_via_item_new():
+    # Ensure mapping creates Sulfuras instance
+    item = Item("Sulfuras, Hand of Ragnaros", sell_in=1, quality=80)
+    assert isinstance(item, Sulfuras)
+
+
+def test_sulfuras_ignores_input_quality_not_80():
+    # Even if we try to pass a non-80 quality, constructor forces 80
+    item = Item("Sulfuras, Hand of Ragnaros", sell_in=1, quality=0)
+    assert item.quality == 80