test: add characterization tests as safety net

python/tests/test_gilded_rose.py

@@ -1,16 +1,64 @@
-# -*- coding: utf-8 -*-
-import unittest
+from gilded_rose import GildedRose, Item
 
-from gilded_rose import Item, GildedRose
+class TestGildedRose:
+    # --- NORMAL ITEMS ---
+    def test_normal_item_quality_decreases_by_1_before_sell_date(self):
+        items = [Item("Normal Item", sell_in=10, quality=20)]
+        GildedRose(items).update_quality()
+        assert items[0].quality == 19
+        assert items[0].sell_in == 9
 
+    def test_normal_item_quality_decreases_by_2_after_sell_date(self):
+        items = [Item("Normal Item", sell_in=0, quality=20)]
+        GildedRose(items).update_quality()
+        assert items[0].quality == 18
 
-class GildedRoseTest(unittest.TestCase):
-    def test_foo(self):
-        items = [Item("foo", 0, 0)]
-        gilded_rose = GildedRose(items)
-        gilded_rose.update_quality()
-        self.assertEqual("fixme", items[0].name)
+    # --- AGED BRIE ---
+    def test_aged_brie_increases_quality_over_time(self):
+        items = [Item("Aged Brie", sell_in=5, quality=10)]
+        GildedRose(items).update_quality()
+        assert items[0].quality == 11
 
+    def test_aged_brie_increases_quality_double_after_sell_in(self):
+        items = [Item("Aged Brie", sell_in=0, quality=10)]
+        GildedRose(items).update_quality()
+        assert items[0].quality == 12
 
-if __name__ == '__main__':
-    unittest.main()
+    # --- SULFURAS ---
+    def test_sulfuras_never_changes(self):
+        items = [Item("Sulfuras, Hand of Ragnaros", sell_in=5, quality=80)]
+        GildedRose(items).update_quality()
+        assert items[0].quality == 80
+        assert items[0].sell_in == 5
+
+    def test_sulfuras_remains_80_after_sell_in(self):
+        items = [Item("Sulfuras, Hand of Ragnaros", sell_in=-1, quality=80)]
+        GildedRose(items).update_quality()
+        assert items[0].quality == 80
+
+    # --- BACKSTAGE PASSES ---
+    def test_backstage_pass_increases_by_2_when_10_days_or_less(self):
+        items = [Item("Backstage passes to a TAFKAL80ETC concert", sell_in=10, quality=20)]
+        GildedRose(items).update_quality()
+        assert items[0].quality == 22
+
+    def test_backstage_pass_increases_by_3_when_5_days_or_less(self):
+        items = [Item("Backstage passes to a TAFKAL80ETC concert", sell_in=5, quality=20)]
+        GildedRose(items).update_quality()
+        assert items[0].quality == 23
+
+    def test_backstage_pass_quality_drops_to_zero_after_concert(self):
+        items = [Item("Backstage passes to a TAFKAL80ETC concert", sell_in=0, quality=20)]
+        GildedRose(items).update_quality()
+        assert items[0].quality == 0
+
+    # --- LÍMITES (EDGE CASES) ---
+    def test_quality_never_goes_below_zero(self):
+        items = [Item("Normal Item", sell_in=5, quality=0)]
+        GildedRose(items).update_quality()
+        assert items[0].quality == 0
+
+    def test_quality_never_exceeds_50(self):
+        items = [Item("Aged Brie", sell_in=5, quality=50)]
+        GildedRose(items).update_quality()
+        assert items[0].quality == 50