Skeleton + tests

menu_orderer.py

+from pprint import pprint
+from typing import List, Tuple
+
+from z3 import *
+
+
+def find_all_orders(menu_items: List[Tuple[str, int]],
+                    goal_price: int) -> List[List[Tuple[str, int]]]:
+    """Find all orders that cost exactly the goal price, given the menu.
+
+    Inspired by https://xkcd.com/287/.
+
+    Args:
+        menu_items (List[Tuple[str, int]]): A list of all menu items and their
+            prices. Assume that all prices are positive.
+        goal_price (int): Desired exact amount to spend.
+
+    Returns:
+        List[List[Tuple[str, int]]]: A list of all orders that cost exactly the
+            goal price. Items not ordered are present with amount 0.
+    """
+    pass
+    # TODO: Implement me!
+
+
+if __name__ == '__main__':
+    pass
+    # You can uncomment the below test cases to try out your implementation,
+    # or add your own scenarios.
+
+    # xkcd_menu = [
+    #     ('mixed_fruit', 215),
+    #     ('french_fries', 275),
+    #     ('side_salad', 335),
+    #     ('hot_wings', 355),
+    #     ('mozz_sticks', 420),
+    #     ('sampler_plate', 580),
+    # ]
+    # goal_price = 1505
+    # pprint(find_all_orders(xkcd_menu, goal_price))
+
+    # red_door_menu = [
+    #     ('avocado_toast', 625),
+    #     ('blue_salad', 725),
+    #     ('chicken_sandwich', 750),
+    #     ('coffee', 230),
+    #     ('mocha', 460),
+    #     ('latte', 400),
+    #     ('hot_chocolate', 300),
+    #     ('chai', 350),
+    #     ('cold_coffee', 500),
+    #     ('brain_freeze', 525)
+    # ]
+    # goal_price = 1315
+    # pprint(find_all_orders(red_door_menu, goal_price))
+
+    # chouse_menu = [
+    #     ('quesadilla', 100),
+    #     ('chicken_nuggets', 300),
+    #     ('burger', 400),
+    #     ('boba', 150),
+    #     ('tofu_nuggets', 150),
+    #     ('fries', 150),
+    #     ('special', 500),
+    #     ('soda', 100),
+    # ]
+    # goal_price = 1025
+    # pprint(find_all_orders(chouse_menu, goal_price))

tests/test_menu_orderer.py

+from typing import List, NamedTuple, Tuple
+
+import menu_orderer
+import pytest
+
+
+class MenuOrdererTestCase(NamedTuple):
+    menu: List[Tuple[str, int]]
+    goal_price: int
+    expected_output: List[List[Tuple[str, int]]]
+
+
+xkcd_287 = MenuOrdererTestCase(
+    menu=[
+        ('mixed_fruit', 215),
+        ('french_fries', 275),
+        ('side_salad', 335),
+        ('hot_wings', 355),
+        ('mozz_sticks', 420),
+        ('sampler_plate', 580),
+    ],
+    goal_price=1505,
+    expected_output=[
+        [
+            ('mixed_fruit', 1),
+            ('french_fries', 0),
+            ('side_salad', 0),
+            ('hot_wings', 2),
+            ('mozz_sticks', 0),
+            ('sampler_plate', 1),
+        ],
+        [
+            ('mixed_fruit', 7),
+            ('french_fries', 0),
+            ('side_salad', 0),
+            ('hot_wings', 0),
+            ('mozz_sticks', 0),
+            ('sampler_plate', 0),
+        ],
+    ],
+)
+
+red_door = MenuOrdererTestCase(
+    menu=[
+        ('avocado_toast', 625),
+        ('blue_salad', 725),
+        ('chicken_sandwich', 750),
+        ('coffee', 230),
+        ('mocha', 460),
+        ('latte', 400),
+        ('hot_chocolate', 300),
+        ('chai', 350),
+        ('cold_coffee', 500),
+        ('brain_freeze', 525),
+    ],
+    goal_price=1315,
+    expected_output=[
+        [
+            ('avocado_toast', 1),
+            ('blue_salad', 0),
+            ('chicken_sandwich', 0),
+            ('coffee', 3),
+            ('mocha', 0),
+            ('latte', 0),
+            ('hot_chocolate', 0),
+            ('chai', 0),
+            ('cold_coffee', 0),
+            ('brain_freeze', 0),
+        ],
+        [
+            ('avocado_toast', 1),
+            ('blue_salad', 0),
+            ('chicken_sandwich', 0),
+            ('coffee', 1),
+            ('mocha', 1),
+            ('latte', 0),
+            ('hot_chocolate', 0),
+            ('chai', 0),
+            ('cold_coffee', 0),
+            ('brain_freeze', 0),
+        ],
+    ],
+)
+
+chouse = MenuOrdererTestCase(
+    menu=[
+        ('quesadilla', 100),
+        ('chicken_nuggets', 300),
+        ('burger', 400),
+        ('boba', 150),
+        ('tofu_nuggets', 150),
+        ('fries', 150),
+        ('special', 500),
+        ('soda', 100),
+    ],
+    goal_price=1025,
+    expected_output=[],
+)
+
+
+# Keep raw data outside the decorator to avoid polluting failed test traceback
+# with irrelevant test data. The relevant data is included regardless.
+@pytest.mark.parametrize('data', [
+    pytest.param(xkcd_287, id='xkcd_287'),
+    pytest.param(red_door, id='red_door'),
+    pytest.param(chouse, id='no_solns:chouse')
+])
+@pytest.mark.timeout(10)
+def test_find_all_orders(data: MenuOrdererTestCase):
+    actual = menu_orderer.find_all_orders(data.menu, data.goal_price)
+    expected = data.expected_output
+
+    # Sort nested lists
+    for e in actual:
+        e.sort()
+    for e in expected:
+        e.sort()
+    
+    # Compare outer sorted lists
+    assert sorted(actual) == sorted(expected)