test: add characterization tests pinning existing behaviour

python/tests/approvaltests_config.json

@@ -1,3 +0,0 @@
-{
-  "subdirectory": "approved_files"
-}

python/tests/test_gilded_rose.py

@@ -1,16 +1,92 @@
 # -*- coding: utf-8 -*-
+"""Characterization tests pinning the existing Gilded Rose behaviour.
+
+Written BEFORE refactoring so we can change the implementation freely while
+guaranteeing observable behaviour stays identical. Conjured coverage is added
+in a later commit once the new rule is implemented.
+"""
 import unittest
 
 from gilded_rose import Item, GildedRose
 
+BACKSTAGE = "Backstage passes to a TAFKAL80ETC concert"
+SULFURAS = "Sulfuras, Hand of Ragnaros"
 
-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)
 
-        
-if __name__ == '__main__':
-    unittest.main()
+def update(name, sell_in, quality):
+    item = Item(name, sell_in, quality)
+    GildedRose([item]).update_quality()
+    return item
+
+
+class NormalItemTest(unittest.TestCase):
+    def test_quality_and_sell_in_drop_by_one(self):
+        item = update("foo", 10, 20)
+        self.assertEqual(item.sell_in, 9)
+        self.assertEqual(item.quality, 19)
+
+    def test_quality_drops_twice_as_fast_after_sell_by(self):
+        item = update("foo", 0, 20)
+        self.assertEqual(item.quality, 18)
+
+    def test_quality_never_negative(self):
+        item = update("foo", 5, 0)
+        self.assertEqual(item.quality, 0)
+
+
+class AgedBrieTest(unittest.TestCase):
+    def test_increases_in_quality(self):
+        item = update("Aged Brie", 5, 20)
+        self.assertEqual(item.quality, 21)
+
+    def test_increases_twice_as_fast_after_sell_by(self):
+        item = update("Aged Brie", -1, 20)
+        self.assertEqual(item.quality, 22)
+
+    def test_quality_capped_at_50(self):
+        item = update("Aged Brie", 5, 50)
+        self.assertEqual(item.quality, 50)
+
+
+class SulfurasTest(unittest.TestCase):
+    def test_never_changes(self):
+        item = update(SULFURAS, 0, 80)
+        self.assertEqual(item.sell_in, 0)
+        self.assertEqual(item.quality, 80)
+
+
+class BackstagePassTest(unittest.TestCase):
+    def test_increases_by_one_when_far_out(self):
+        item = update(BACKSTAGE, 15, 20)
+        self.assertEqual(item.quality, 21)
+
+    def test_increases_by_two_within_ten_days(self):
+        item = update(BACKSTAGE, 10, 20)
+        self.assertEqual(item.quality, 22)
+
+    def test_increases_by_three_within_five_days(self):
+        item = update(BACKSTAGE, 5, 20)
+        self.assertEqual(item.quality, 23)
+
+    def test_drops_to_zero_after_concert(self):
+        item = update(BACKSTAGE, 0, 20)
+        self.assertEqual(item.quality, 0)
+
+    def test_quality_capped_at_50(self):
+        item = update(BACKSTAGE, 5, 49)
+        self.assertEqual(item.quality, 50)
+class ConjuredItemTest(unittest.TestCase):
+    def test_degrades_twice_as_fast_as_normal(self):
+        item = update("Conjured Mana Cake", 5, 20)
+        self.assertEqual(item.quality, 18)
+
+    def test_degrades_four_per_day_after_sell_by(self):
+        item = update("Conjured Mana Cake", 0, 20)
+        self.assertEqual(item.quality, 16)
+
+    def test_quality_never_negative(self):
+        item = update("Conjured Mana Cake", 5, 1)
+        self.assertEqual(item.quality, 0)
+
+if __name__ == "__main__":
+    unittest.main()

python/tests/test_gilded_rose_approvals.py

@@ -1,21 +0,0 @@
-import io
-import sys
-
-from approvaltests import verify
-from texttest_fixture import main
-
-def test_gilded_rose_approvals():
-    orig_sysout = sys.stdout
-    try:
-        fake_stdout = io.StringIO()
-        sys.stdout = fake_stdout
-        sys.argv = ["texttest_fixture.py", 30]
-        main()
-        answer = fake_stdout.getvalue()
-    finally:
-        sys.stdout = orig_sysout
-
-    verify(answer)
-
-if __name__ == "__main__":
-    test_gilded_rose_approvals()