diff --git a/python/README.md b/python/README.md index 0f08e87f..b836b36f 100644 --- a/python/README.md +++ b/python/README.md @@ -37,3 +37,43 @@ python tests/test_gilded_rose_approvals.py ``` You will need to approve the output file which appears under "approved_files" by renaming it from xxx.received.txt to xxx.approved.txt. + +The Gilded Rose is a refactoring Kata. The simplest way to start would be to go to the [github repo](https://github.com/emilybache/GildedRose-Refactoring-Kata), clone it and start hacking away! The requirement specifications are below. + +Gilded Rose Requirements Specification +====================================== + +Hi and welcome to team Gilded Rose. As you know, we are a small inn with a prime location in a +prominent city ran by a friendly innkeeper named Allison. We also buy and sell only the finest goods. +Unfortunately, our goods are constantly degrading in quality as they approach their sell by date. We +have a system in place that updates our inventory for us. It was developed by a no-nonsense type named +Leeroy, who has moved on to new adventures. Your task is to add the new feature to our system so that +we can begin selling a new category of items. First an introduction to our system: + + - All items have a SellIn value which denotes the number of days we have to sell the item + - All items have a Quality value which denotes how valuable the item is + - At the end of each day our system lowers both values for every item + +Pretty simple, right? Well this is where it gets interesting: + + - Once the sell by date has passed, Quality degrades twice as fast + - The Quality of an item is never negative + - "Aged Brie" actually increases in Quality the older it gets + - The Quality of an item is never more than 50 + - "Sulfuras", being a legendary item, never has to be sold or decreases in Quality + - "Backstage passes", like aged brie, increases in Quality as its SellIn value approaches; + Quality increases by 2 when there are 10 days or less and by 3 when there are 5 days or less but + Quality drops to 0 after the concert + +We have recently signed a supplier of conjured items. This requires an update to our system: + + - "Conjured" items degrade in Quality twice as fast as normal items + +Feel free to make any changes to the UpdateQuality method and add any new code as long as everything +still works correctly. However, do not alter the Item class or Items property as those belong to the +goblin in the corner who will insta-rage and one-shot you as he doesn't believe in shared code +ownership (you can make the UpdateQuality method and Items property static if you like, we'll cover +for you). + +Just for clarification, an item can never have its Quality increase above 50, however "Sulfuras" is a +legendary item and as such its Quality is 80 and it never alters. diff --git a/python/plans/gilded-rose-strategy-refactor.md b/python/plans/gilded-rose-strategy-refactor.md new file mode 100644 index 00000000..d017c2f4 --- /dev/null +++ b/python/plans/gilded-rose-strategy-refactor.md @@ -0,0 +1,825 @@ +# GildedRose Strategy Pattern Refactor — Implementation Plan + +> **For agentic workers:** REQUIRED SUB-SKILL: Use superpowers:subagent-driven-development (recommended) or superpowers:executing-plans to implement this plan task-by-task. Steps use checkbox (`- [ ]`) syntax for tracking. + +**Goal:** Refactor `GildedRose.update_quality` from a nested if/elif chain into a Strategy Pattern with an internal `ItemRecord` dataclass, `days` injection, and full test coverage including the new Conjured item type. + +**Architecture:** Each item type gets a dedicated `UpdateStrategy` class. `GildedRose.__init__` wraps every `Item` in an internal `ItemRecord(item, strategy)` by looking up the item name in a dict; unknowns get `NormalStrategy`. `update_quality(days=1)` delegates to each record's strategy, simulating `days` days in one call. + +**Tech Stack:** Python 3.10+, `unittest.TestCase`, `pytest`, `dataclasses`, `typing.Protocol` + +--- + +## File Map + +| File | Change | +|---|---| +| `gilded_rose.py` | Add `UpdateStrategy` Protocol, five strategy classes, `ItemRecord` dataclass, `_STRATEGY_MAP`, refactor `GildedRose` | +| `tests/test_gilded_rose.py` | Fix `test_foo`, add one `TestCase` per strategy class + integration `TestGildedRose` | + +--- + +### Task 1: Fix the broken placeholder test + +**Files:** +- Modify: `tests/test_gilded_rose.py` + +The existing `test_foo` always fails because it asserts `items[0].name == "fixme"` — `update_quality` never changes names. Fix it to assert the real behaviour: a normal item with `quality=0` stays at `0` after one update. + +- [ ] **Step 1: Update the assertion and rename the test** + +Replace the test body in `tests/test_gilded_rose.py`: + +```python +class GildedRoseTest(unittest.TestCase): + def test_normal_item_at_zero_quality_stays_zero(self): + items = [Item("foo", 0, 0)] + gilded_rose = GildedRose(items) + gilded_rose.update_quality() + self.assertEqual(0, items[0].quality) +``` + +- [ ] **Step 2: Run the test and confirm it passes** + +```bash +cd /Users/rajvora/Documents/interviews/GildedRose-Refactoring-Kata/python +python3 -m pytest tests/test_gilded_rose.py -v +``` + +Expected: `PASSED tests/test_gilded_rose.py::GildedRoseTest::test_normal_item_at_zero_quality_stays_zero` + +- [ ] **Step 3: Commit** + +```bash +git add tests/test_gilded_rose.py +git commit -m "fix: correct placeholder test_foo assertion" +``` + +--- + +### Task 2: NormalStrategy — TDD + +**Files:** +- Modify: `tests/test_gilded_rose.py` — add `TestNormalStrategy` +- Modify: `gilded_rose.py` — add `NormalStrategy` + +Normal items: `-1 quality/day`, `-2/day` once `sell_in < 0`, quality floors at `0`. + +- [ ] **Step 1: Write failing tests for NormalStrategy** + +Add this class to `tests/test_gilded_rose.py` (after the existing `GildedRoseTest`): + +```python +class TestNormalStrategy(unittest.TestCase): + """Tests for NormalStrategy — default degradation behaviour.""" + + def setUp(self): + self.strategy = NormalStrategy() + + def test_quality_decrements_by_one_each_day(self): + item = Item("widget", sell_in=10, quality=20) + self.strategy.update(item, days=1) + self.assertEqual(19, item.quality) + self.assertEqual(9, item.sell_in) + + def test_quality_floors_at_zero(self): + # Quality must never go negative + item = Item("widget", sell_in=5, quality=0) + self.strategy.update(item, days=1) + self.assertEqual(0, item.quality) + + def test_quality_degrades_twice_after_sell_date(self): + # Once sell_in goes below 0, each day removes 2 quality + item = Item("widget", sell_in=0, quality=10) + self.strategy.update(item, days=1) + self.assertEqual(8, item.quality) + self.assertEqual(-1, item.sell_in) + + def test_multi_day_crosses_sell_date(self): + # Days=5 starting from sell_in=2: 2 normal days then 3 post-sell days + # Day1: q=9 si=1 | Day2: q=8 si=0 | Day3: q=6 si=-1 + # Day4: q=4 si=-2 | Day5: q=2 si=-3 + item = Item("widget", sell_in=2, quality=10) + self.strategy.update(item, days=5) + self.assertEqual(2, item.quality) + self.assertEqual(-3, item.sell_in) + + def test_quality_floors_at_zero_when_crossing_sell_date(self): + item = Item("widget", sell_in=1, quality=1) + # Day1: q=0 si=0 | Day2: post-sell but already 0 + self.strategy.update(item, days=2) + self.assertEqual(0, item.quality) +``` + +Also update the import line at the top of the test file to include `NormalStrategy`: + +```python +from gilded_rose import Item, GildedRose, NormalStrategy +``` + +- [ ] **Step 2: Run tests to confirm they FAIL** + +```bash +python3 -m pytest tests/test_gilded_rose.py::TestNormalStrategy -v +``` + +Expected: `ImportError` or `AttributeError` — `NormalStrategy` does not exist yet. + +- [ ] **Step 3: Implement NormalStrategy in gilded_rose.py** + +Add at the top of `gilded_rose.py` (before the `GildedRose` class, after any existing code): + +```python +# -*- coding: utf-8 -*- +from dataclasses import dataclass +from typing import Protocol + + +class UpdateStrategy(Protocol): + """Interface for per-item-type quality update logic.""" + + def update(self, item: "Item", days: int) -> None: + """Mutate item.quality and item.sell_in to reflect `days` passing.""" + ... + + +class NormalStrategy: + """ + Default degradation strategy. + + Quality decreases by 1 per day; by 2 per day once the sell date + has passed (sell_in < 0). Quality never falls below 0. + """ + + def update(self, item: "Item", days: int) -> None: + for _ in range(days): + item.quality = max(0, item.quality - 1) + item.sell_in -= 1 + if item.sell_in < 0: + item.quality = max(0, item.quality - 1) +``` + +- [ ] **Step 4: Run tests to confirm they PASS** + +```bash +python3 -m pytest tests/test_gilded_rose.py::TestNormalStrategy -v +``` + +Expected: all 5 tests `PASSED`. + +- [ ] **Step 5: Run full suite to confirm no regressions** + +```bash +python3 -m pytest tests/ -v +``` + +Expected: all tests pass. + +- [ ] **Step 6: Commit** + +```bash +git add gilded_rose.py tests/test_gilded_rose.py +git commit -m "feat: add NormalStrategy with days injection" +``` + +--- + +### Task 3: AgedBrieStrategy — TDD + +**Files:** +- Modify: `tests/test_gilded_rose.py` — add `TestAgedBrieStrategy` +- Modify: `gilded_rose.py` — add `AgedBrieStrategy` + +Aged Brie: `+1 quality/day`, `+2/day` after sell date, caps at `50`. + +- [ ] **Step 1: Write failing tests** + +Add to the import line: + +```python +from gilded_rose import Item, GildedRose, NormalStrategy, AgedBrieStrategy +``` + +Add this class: + +```python +class TestAgedBrieStrategy(unittest.TestCase): + """Tests for AgedBrieStrategy — quality improves with age.""" + + def setUp(self): + self.strategy = AgedBrieStrategy() + + def test_quality_increments_by_one_each_day(self): + item = Item("Aged Brie", sell_in=10, quality=20) + self.strategy.update(item, days=1) + self.assertEqual(21, item.quality) + self.assertEqual(9, item.sell_in) + + def test_quality_caps_at_50(self): + item = Item("Aged Brie", sell_in=10, quality=50) + self.strategy.update(item, days=1) + self.assertEqual(50, item.quality) + + def test_quality_increments_twice_after_sell_date(self): + # Past sell date: +2 per day + item = Item("Aged Brie", sell_in=0, quality=20) + self.strategy.update(item, days=1) + self.assertEqual(22, item.quality) + self.assertEqual(-1, item.sell_in) + + def test_multi_day_crosses_sell_date(self): + # sell_in=1, quality=46, days=3 + # Day1: q=47 si=0 | Day2: q=49 si=-1 | Day3: q=50 (capped) si=-2 + item = Item("Aged Brie", sell_in=1, quality=46) + self.strategy.update(item, days=3) + self.assertEqual(50, item.quality) + self.assertEqual(-2, item.sell_in) +``` + +- [ ] **Step 2: Run tests to confirm they FAIL** + +```bash +python3 -m pytest tests/test_gilded_rose.py::TestAgedBrieStrategy -v +``` + +Expected: `ImportError` — `AgedBrieStrategy` does not exist yet. + +- [ ] **Step 3: Implement AgedBrieStrategy in gilded_rose.py** + +Add after `NormalStrategy`: + +```python +class AgedBrieStrategy: + """ + Quality improvement strategy for Aged Brie. + + Quality increases by 1 per day; by 2 per day once the sell date + has passed. Quality never exceeds 50. + """ + + def update(self, item: "Item", days: int) -> None: + for _ in range(days): + item.quality = min(50, item.quality + 1) + item.sell_in -= 1 + if item.sell_in < 0: + item.quality = min(50, item.quality + 1) +``` + +- [ ] **Step 4: Run tests to confirm they PASS** + +```bash +python3 -m pytest tests/test_gilded_rose.py::TestAgedBrieStrategy -v +``` + +Expected: all 4 tests `PASSED`. + +- [ ] **Step 5: Run full suite** + +```bash +python3 -m pytest tests/ -v +``` + +- [ ] **Step 6: Commit** + +```bash +git add gilded_rose.py tests/test_gilded_rose.py +git commit -m "feat: add AgedBrieStrategy" +``` + +--- + +### Task 4: BackstagePassStrategy — TDD + +**Files:** +- Modify: `tests/test_gilded_rose.py` — add `TestBackstagePassStrategy` +- Modify: `gilded_rose.py` — add `BackstagePassStrategy` + +Rules: `+1` quality normally; `+2` when `sell_in ≤ 10`; `+3` when `sell_in ≤ 5`; drops to `0` when `sell_in` reaches `0` at start of day (concert day). Quality caps at `50`. + +- [ ] **Step 1: Write failing tests** + +Update import: + +```python +from gilded_rose import ( + Item, GildedRose, NormalStrategy, AgedBrieStrategy, + BackstagePassStrategy, +) +``` + +Add: + +```python +class TestBackstagePassStrategy(unittest.TestCase): + """Tests for BackstagePassStrategy — tiered increase, zeroes after concert.""" + + def setUp(self): + self.strategy = BackstagePassStrategy() + + def test_quality_increments_by_1_when_more_than_10_days(self): + item = Item("Backstage passes to a TAFKAL80ETC concert", sell_in=15, quality=20) + self.strategy.update(item, days=1) + self.assertEqual(21, item.quality) + self.assertEqual(14, item.sell_in) + + def test_quality_increments_by_2_when_10_or_fewer_days(self): + item = Item("Backstage passes to a TAFKAL80ETC concert", sell_in=10, quality=20) + self.strategy.update(item, days=1) + self.assertEqual(22, item.quality) + self.assertEqual(9, item.sell_in) + + def test_quality_increments_by_3_when_5_or_fewer_days(self): + item = Item("Backstage passes to a TAFKAL80ETC concert", sell_in=5, quality=20) + self.strategy.update(item, days=1) + self.assertEqual(23, item.quality) + self.assertEqual(4, item.sell_in) + + def test_quality_drops_to_zero_on_concert_day(self): + # sell_in=0 means the concert is today — quality zeroes out + item = Item("Backstage passes to a TAFKAL80ETC concert", sell_in=0, quality=30) + self.strategy.update(item, days=1) + self.assertEqual(0, item.quality) + self.assertEqual(-1, item.sell_in) + + def test_quality_stays_zero_after_concert(self): + item = Item("Backstage passes to a TAFKAL80ETC concert", sell_in=-1, quality=0) + self.strategy.update(item, days=1) + self.assertEqual(0, item.quality) + + def test_quality_caps_at_50(self): + item = Item("Backstage passes to a TAFKAL80ETC concert", sell_in=5, quality=49) + self.strategy.update(item, days=1) + self.assertEqual(50, item.quality) + + def test_multi_day_crosses_all_thresholds(self): + # sell_in=12, quality=20, days=4 + # Day1(si=12): +1 → q=21, si=11 + # Day2(si=11): +1 → q=22, si=10 + # Day3(si=10): +2 → q=24, si=9 + # Day4(si=9): +2 → q=26, si=8 + item = Item("Backstage passes to a TAFKAL80ETC concert", sell_in=12, quality=20) + self.strategy.update(item, days=4) + self.assertEqual(26, item.quality) + self.assertEqual(8, item.sell_in) +``` + +- [ ] **Step 2: Run tests to confirm they FAIL** + +```bash +python3 -m pytest tests/test_gilded_rose.py::TestBackstagePassStrategy -v +``` + +Expected: `ImportError` — `BackstagePassStrategy` not defined. + +- [ ] **Step 3: Implement BackstagePassStrategy** + +Add after `AgedBrieStrategy`: + +```python +class BackstagePassStrategy: + """ + Quality strategy for backstage passes. + + Quality increases as the concert approaches: + - +1/day when more than 10 days remain + - +2/day when 10 or fewer days remain + - +3/day when 5 or fewer days remain + Quality drops to 0 on concert day (sell_in == 0 at start of day) + and stays 0 afterwards. Quality never exceeds 50. + """ + + def update(self, item: "Item", days: int) -> None: + for _ in range(days): + if item.sell_in <= 0: + # Concert day or past — quality is worthless + item.quality = 0 + item.sell_in -= 1 + continue + if item.sell_in <= 5: + item.quality = min(50, item.quality + 3) + elif item.sell_in <= 10: + item.quality = min(50, item.quality + 2) + else: + item.quality = min(50, item.quality + 1) + item.sell_in -= 1 +``` + +- [ ] **Step 4: Run tests to confirm they PASS** + +```bash +python3 -m pytest tests/test_gilded_rose.py::TestBackstagePassStrategy -v +``` + +Expected: all 7 tests `PASSED`. + +- [ ] **Step 5: Run full suite** + +```bash +python3 -m pytest tests/ -v +``` + +- [ ] **Step 6: Commit** + +```bash +git add gilded_rose.py tests/test_gilded_rose.py +git commit -m "feat: add BackstagePassStrategy" +``` + +--- + +### Task 5: SulfurasStrategy — TDD + +**Files:** +- Modify: `tests/test_gilded_rose.py` — add `TestSulfurasStrategy` +- Modify: `gilded_rose.py` — add `SulfurasStrategy` + +Sulfuras is legendary: `quality` is always `80`, `sell_in` never changes. + +- [ ] **Step 1: Write failing tests** + +Update import: + +```python +from gilded_rose import ( + Item, GildedRose, NormalStrategy, AgedBrieStrategy, + BackstagePassStrategy, SulfurasStrategy, +) +``` + +Add: + +```python +class TestSulfurasStrategy(unittest.TestCase): + """Tests for SulfurasStrategy — legendary item, never changes.""" + + def setUp(self): + self.strategy = SulfurasStrategy() + + def test_quality_never_changes(self): + item = Item("Sulfuras, Hand of Ragnaros", sell_in=0, quality=80) + self.strategy.update(item, days=1) + self.assertEqual(80, item.quality) + + def test_sell_in_never_changes(self): + item = Item("Sulfuras, Hand of Ragnaros", sell_in=0, quality=80) + self.strategy.update(item, days=1) + self.assertEqual(0, item.sell_in) + + def test_unchanged_after_many_days(self): + item = Item("Sulfuras, Hand of Ragnaros", sell_in=0, quality=80) + self.strategy.update(item, days=100) + self.assertEqual(80, item.quality) + self.assertEqual(0, item.sell_in) +``` + +- [ ] **Step 2: Run tests to confirm they FAIL** + +```bash +python3 -m pytest tests/test_gilded_rose.py::TestSulfurasStrategy -v +``` + +Expected: `ImportError`. + +- [ ] **Step 3: Implement SulfurasStrategy** + +Add after `BackstagePassStrategy`: + +```python +class SulfurasStrategy: + """ + No-op strategy for Sulfuras, Hand of Ragnaros. + + Legendary items never degrade and never need to be sold. + Neither quality nor sell_in is ever mutated. + """ + + def update(self, item: "Item", days: int) -> None: + pass # legendary items are immutable +``` + +- [ ] **Step 4: Run tests to confirm they PASS** + +```bash +python3 -m pytest tests/test_gilded_rose.py::TestSulfurasStrategy -v +``` + +Expected: all 3 tests `PASSED`. + +- [ ] **Step 5: Run full suite** + +```bash +python3 -m pytest tests/ -v +``` + +- [ ] **Step 6: Commit** + +```bash +git add gilded_rose.py tests/test_gilded_rose.py +git commit -m "feat: add SulfurasStrategy" +``` + +--- + +### Task 6: ConjuredStrategy — TDD + +**Files:** +- Modify: `tests/test_gilded_rose.py` — add `TestConjuredStrategy` +- Modify: `gilded_rose.py` — add `ConjuredStrategy` + +Conjured items degrade at twice the normal rate: `-2/day`, `-4/day` after sell date. Quality floors at `0`. + +- [ ] **Step 1: Write failing tests** + +Update import: + +```python +from gilded_rose import ( + Item, GildedRose, NormalStrategy, AgedBrieStrategy, + BackstagePassStrategy, SulfurasStrategy, ConjuredStrategy, +) +``` + +Add: + +```python +class TestConjuredStrategy(unittest.TestCase): + """Tests for ConjuredStrategy — degrades twice as fast as normal.""" + + def setUp(self): + self.strategy = ConjuredStrategy() + + def test_quality_decrements_by_2_each_day(self): + item = Item("Conjured Mana Cake", sell_in=10, quality=20) + self.strategy.update(item, days=1) + self.assertEqual(18, item.quality) + self.assertEqual(9, item.sell_in) + + def test_quality_floors_at_zero(self): + item = Item("Conjured Mana Cake", sell_in=5, quality=1) + self.strategy.update(item, days=1) + self.assertEqual(0, item.quality) + + def test_quality_degrades_by_4_after_sell_date(self): + # Past sell date: -4 per day + item = Item("Conjured Mana Cake", sell_in=0, quality=20) + self.strategy.update(item, days=1) + self.assertEqual(16, item.quality) + self.assertEqual(-1, item.sell_in) + + def test_multi_day_crosses_sell_date(self): + # sell_in=1, quality=10, days=3 + # Day1: q=8 si=0 | Day2: q=4 si=-1 | Day3: q=0 si=-2 + item = Item("Conjured Mana Cake", sell_in=1, quality=10) + self.strategy.update(item, days=3) + self.assertEqual(0, item.quality) + self.assertEqual(-2, item.sell_in) + + def test_quality_floors_at_zero_post_sell_date(self): + item = Item("Conjured Mana Cake", sell_in=0, quality=2) + self.strategy.update(item, days=1) + self.assertEqual(0, item.quality) +``` + +- [ ] **Step 2: Run tests to confirm they FAIL** + +```bash +python3 -m pytest tests/test_gilded_rose.py::TestConjuredStrategy -v +``` + +Expected: `ImportError`. + +- [ ] **Step 3: Implement ConjuredStrategy** + +Add after `SulfurasStrategy`: + +```python +class ConjuredStrategy: + """ + Double-degradation strategy for Conjured items. + + Quality decreases by 2 per day; by 4 per day once the sell date + has passed. Quality never falls below 0. + """ + + def update(self, item: "Item", days: int) -> None: + for _ in range(days): + item.quality = max(0, item.quality - 2) + item.sell_in -= 1 + if item.sell_in < 0: + item.quality = max(0, item.quality - 2) +``` + +- [ ] **Step 4: Run tests to confirm they PASS** + +```bash +python3 -m pytest tests/test_gilded_rose.py::TestConjuredStrategy -v +``` + +Expected: all 5 tests `PASSED`. + +- [ ] **Step 5: Run full suite** + +```bash +python3 -m pytest tests/ -v +``` + +- [ ] **Step 6: Commit** + +```bash +git add gilded_rose.py tests/test_gilded_rose.py +git commit -m "feat: add ConjuredStrategy" +``` + +--- + +### Task 7: Wire GildedRose to use strategies — TDD + +**Files:** +- Modify: `gilded_rose.py` — add `ItemRecord`, `_STRATEGY_MAP`, refactor `GildedRose` +- Modify: `tests/test_gilded_rose.py` — add `TestGildedRose` integration tests + +This is the wiring step: `GildedRose` replaces its monolithic `update_quality` body with strategy dispatch via `ItemRecord`. + +- [ ] **Step 1: Write failing integration tests** + +Update import to add `ItemRecord`: + +```python +from gilded_rose import ( + Item, GildedRose, NormalStrategy, AgedBrieStrategy, + BackstagePassStrategy, SulfurasStrategy, ConjuredStrategy, + ItemRecord, +) +``` + +Add: + +```python +class TestGildedRose(unittest.TestCase): + """ + Integration tests for GildedRose. + + Verifies strategy dispatch by name and that the days parameter + is forwarded correctly. + """ + + def test_dispatches_normal_strategy_for_unknown_item(self): + items = [Item("unknown widget", sell_in=5, quality=10)] + GildedRose(items).update_quality() + self.assertEqual(9, items[0].quality) + self.assertEqual(4, items[0].sell_in) + + def test_dispatches_aged_brie_strategy(self): + items = [Item("Aged Brie", sell_in=5, quality=20)] + GildedRose(items).update_quality() + self.assertEqual(21, items[0].quality) + + def test_dispatches_backstage_pass_strategy(self): + items = [Item("Backstage passes to a TAFKAL80ETC concert", sell_in=5, quality=20)] + GildedRose(items).update_quality() + self.assertEqual(23, items[0].quality) + + def test_dispatches_sulfuras_strategy(self): + items = [Item("Sulfuras, Hand of Ragnaros", sell_in=0, quality=80)] + GildedRose(items).update_quality() + self.assertEqual(80, items[0].quality) + self.assertEqual(0, items[0].sell_in) + + def test_dispatches_conjured_strategy(self): + items = [Item("Conjured Mana Cake", sell_in=5, quality=20)] + GildedRose(items).update_quality() + self.assertEqual(18, items[0].quality) + + def test_multi_day_update_via_days_param(self): + items = [Item("unknown widget", sell_in=3, quality=10)] + GildedRose(items).update_quality(days=3) + # Day1: q=9 si=2 | Day2: q=8 si=1 | Day3: q=7 si=0 + self.assertEqual(7, items[0].quality) + self.assertEqual(0, items[0].sell_in) + + def test_multiple_items_updated_independently(self): + items = [ + Item("Aged Brie", sell_in=5, quality=20), + Item("unknown widget", sell_in=5, quality=20), + ] + GildedRose(items).update_quality() + self.assertEqual(21, items[0].quality) # Aged Brie goes up + self.assertEqual(19, items[1].quality) # normal goes down + + def test_item_record_allows_direct_strategy_injection(self): + # Verify ItemRecord can be used to inject a strategy directly in tests + item = Item("anything", sell_in=5, quality=20) + record = ItemRecord(item=item, strategy=ConjuredStrategy()) + record.strategy.update(record.item, days=1) + self.assertEqual(18, item.quality) +``` + +- [ ] **Step 2: Run tests to confirm they FAIL** + +```bash +python3 -m pytest tests/test_gilded_rose.py::TestGildedRose -v +``` + +Expected: `ImportError` for `ItemRecord`; or `TypeError` on `update_quality(days=3)` since the current implementation doesn't accept `days`. + +- [ ] **Step 3: Refactor GildedRose in gilded_rose.py** + +Replace the entire `GildedRose` class with the following (keep `Item` class unchanged at the bottom of the file): + +```python +_STRATEGY_MAP: dict[str, UpdateStrategy] = { + "Aged Brie": AgedBrieStrategy(), + "Backstage passes to a TAFKAL80ETC concert": BackstagePassStrategy(), + "Sulfuras, Hand of Ragnaros": SulfurasStrategy(), + "Conjured Mana Cake": ConjuredStrategy(), +} + + +@dataclass +class ItemRecord: + """ + Internal pairing of an Item with its UpdateStrategy. + + Built once in GildedRose.__init__ so the name-to-strategy lookup + happens at construction time, not on every update call. + Exposed publicly so tests can inject strategies directly without + going through the name-lookup dict. + """ + + item: Item + strategy: UpdateStrategy + + +class GildedRose: + """ + Inventory manager for the Gilded Rose inn. + + Accepts a list of Item objects and updates their quality and sell_in + values according to each item's type-specific strategy. The Item + class and the items list are left untouched per the goblin's terms. + + Usage: + rose = GildedRose(items) + rose.update_quality() # advance one day + rose.update_quality(days=7) # advance a full week + """ + + def __init__(self, items: list[Item]) -> None: + self.items = items + self._records: list[ItemRecord] = [ + ItemRecord( + item=i, + strategy=_STRATEGY_MAP.get(i.name, NormalStrategy()), + ) + for i in items + ] + + def update_quality(self, days: int = 1) -> None: + """Advance quality and sell_in for all items by `days` days.""" + for record in self._records: + record.strategy.update(record.item, days) +``` + +- [ ] **Step 4: Run integration tests to confirm they PASS** + +```bash +python3 -m pytest tests/test_gilded_rose.py::TestGildedRose -v +``` + +Expected: all 8 tests `PASSED`. + +- [ ] **Step 5: Run full suite to confirm all tests pass** + +```bash +python3 -m pytest tests/ -v +``` + +Expected: all tests across all `TestCase` classes `PASSED`. + +- [ ] **Step 6: Commit** + +```bash +git add gilded_rose.py tests/test_gilded_rose.py +git commit -m "feat: refactor GildedRose with Strategy pattern and ItemRecord" +``` + +--- + +## Verification + +Run the full suite from the project root: + +```bash +cd /Users/rajvora/Documents/interviews/GildedRose-Refactoring-Kata/python +python3 -m pytest tests/ -v +``` + +Expected output: all tests in `GildedRoseTest`, `TestNormalStrategy`, `TestAgedBrieStrategy`, `TestBackstagePassStrategy`, `TestSulfurasStrategy`, `TestConjuredStrategy`, and `TestGildedRose` show `PASSED`. + +Also verify the texttest fixture still runs: + +```bash +python3 texttest_fixture.py 5 +``` + +Expected: 5 days of inventory output with no errors.