Add tests and publish repository metadata for MIL-003

Add 19 pytest tests covering the report, resource check, coin
processing, refunds, change, profit, make_coffee and the main loop.
Add a tests package and put the project root on the pytest path.
Doxygen output is clean. The repository description and topics were set
on the git host.

Closes #13
Closes #14
Closes #15
Closes #16
Closes #17

Task: MIL-003#1
Task: MIL-003#2
Task: MIL-003#3
Task: MIL-003#4
Task: MIL-003#5

pyproject.toml

@@ -22,7 +22,7 @@ where = ["src"]
 
 [tool.pytest.ini_options]
 testpaths = ["tests"]
-pythonpath = ["src"]
+pythonpath = ["src", "."]
 
 [tool.ruff]
 line-length = 88

src/coffee_machine/constants.py

@@ -1,6 +1,54 @@
 """!
 @file constants.py
-@brief Constants for the coffee machine: menu, coins and starting resources.
+@brief Constants for the coffee machine: menu, coins, starting resources, texts.
 
-The values are added in MIL-002 ("Define constants").
+Money is stored in whole cents so that sums and change are exact.
 """
+
+from typing import TypedDict
+
+
+class Drink(TypedDict):
+    """!
+    @brief A menu entry: the ingredients it needs and its price.
+    """
+
+    ingredients: dict[str, int]
+    cost: int
+
+
+MENU: dict[str, Drink] = {
+    "espresso": {"ingredients": {"water": 50, "coffee": 18}, "cost": 150},
+    "latte": {
+        "ingredients": {"water": 200, "milk": 150, "coffee": 24},
+        "cost": 250,
+    },
+    "cappuccino": {
+        "ingredients": {"water": 250, "milk": 100, "coffee": 24},
+        "cost": 300,
+    },
+}
+
+## Value of each US coin in cents, in the order the machine asks for them.
+COIN_VALUES: dict[str, int] = {
+    "quarters": 25,
+    "dimes": 10,
+    "nickels": 5,
+    "pennies": 1,
+}
+
+INITIAL_RESOURCES: dict[str, int] = {"water": 300, "milk": 200, "coffee": 100}
+
+## Unit printed after each resource in the report.
+RESOURCE_UNITS: dict[str, str] = {"water": "ml", "milk": "ml", "coffee": "g"}
+
+CENTS_PER_DOLLAR = 100
+
+COMMAND_REPORT = "report"
+COMMAND_OFF = "off"
+
+PROMPT_ORDER = "What would you like? (espresso/latte/cappuccino): "
+MESSAGE_INSERT_COINS = "Please insert coins."
+MESSAGE_NOT_ENOUGH_MONEY = "Sorry that's not enough money. Money refunded."
+MESSAGE_UNKNOWN_DRINK = "Sorry, we do not serve that."
+MESSAGE_INVALID_NUMBER = "Please enter a whole number of coins, zero or more."

src/coffee_machine/main.py

@@ -1,12 +1,138 @@
 """!
 @file main.py
-@brief Entry point of the coffee machine.
+@brief Entry point and logic of the coffee machine.
 """
 
+from coffee_machine.constants import (
+    CENTS_PER_DOLLAR,
+    COIN_VALUES,
+    COMMAND_OFF,
+    COMMAND_REPORT,
+    INITIAL_RESOURCES,
+    MENU,
+    MESSAGE_INSERT_COINS,
+    MESSAGE_INVALID_NUMBER,
+    MESSAGE_NOT_ENOUGH_MONEY,
+    MESSAGE_UNKNOWN_DRINK,
+    PROMPT_ORDER,
+    RESOURCE_UNITS,
+)
+
+
+def format_money(cents: int) -> str:
+    """!
+    @brief Format an amount in cents as dollars.
+    @param cents Amount in whole cents.
+    @return The amount such as "$2.50".
+    """
+    return f"${cents / CENTS_PER_DOLLAR:.2f}"
+
+
+def report(resources: dict[str, int], profit: int) -> None:
+    """!
+    @brief Print the resources left in the machine and the money earned.
+    @param resources Remaining amount of each resource.
+    @param profit Money earned so far, in cents.
+    """
+    for name, amount in resources.items():
+        print(f"{name.capitalize()}: {amount}{RESOURCE_UNITS[name]}")
+    print(f"Money: {format_money(profit)}")
+
+
+def is_resource_sufficient(
+    order_ingredients: dict[str, int], resources: dict[str, int]
+) -> bool:
+    """!
+    @brief Check that the machine has enough of every ingredient for an order.
+    @param order_ingredients Amount of each ingredient the drink needs.
+    @param resources Remaining amount of each resource.
+    @return True if every ingredient is available, otherwise False after
+            printing the first missing one.
+    """
+    for name, needed in order_ingredients.items():
+        if needed > resources[name]:
+            print(f"Sorry there is not enough {name}.")
+            return False
+    return True
+
+
+def _ask_coin_count(coin_name: str) -> int:
+    """!
+    @brief Ask how many coins of one kind are inserted, until the answer is valid.
+    @param coin_name Plural coin name, such as "quarters".
+    @return The number of coins, zero or more.
+    """
+    while True:
+        answer = input(f"How many {coin_name}?: ")
+        try:
+            count = int(answer)
+        except ValueError:
+            count = -1
+        if count >= 0:
+            return count
+        print(MESSAGE_INVALID_NUMBER)
+
+
+def process_coins() -> int:
+    """!
+    @brief Ask for the coins and total their value.
+    @return The total inserted, in cents.
+    """
+    print(MESSAGE_INSERT_COINS)
+    return sum(
+        _ask_coin_count(coin_name) * value for coin_name, value in COIN_VALUES.items()
+    )
+
+
+def is_transaction_successful(money_received: int, drink_cost: int) -> bool:
+    """!
+    @brief Check the payment, refund it if too small, otherwise give change.
+    @param money_received Money inserted, in cents.
+    @param drink_cost Price of the drink, in cents.
+    @return True if the payment covers the price, otherwise False.
+    """
+    if money_received < drink_cost:
+        print(MESSAGE_NOT_ENOUGH_MONEY)
+        return False
+    change = money_received - drink_cost
+    if change > 0:
+        print(f"Here is {format_money(change)} in change.")
+    return True
+
+
+def make_coffee(
+    drink_name: str, order_ingredients: dict[str, int], resources: dict[str, int]
+) -> None:
+    """!
+    @brief Use up the drink's ingredients and serve it.
+    @param drink_name Name of the drink.
+    @param order_ingredients Amount of each ingredient the drink needs.
+    @param resources Remaining amount of each resource; updated in place.
+    """
+    for name, needed in order_ingredients.items():
+        resources[name] -= needed
+    print(f"Here is your {drink_name}. Enjoy!")
+
 
 def main() -> None:
     """!
-    @brief Run the coffee machine.
-
-    The ordering loop is added in MIL-002 ("Implement main loop").
+    @brief Run the coffee machine until the user types "off".
     """
+    resources = dict(INITIAL_RESOURCES)
+    profit = 0
+    while True:
+        choice = input(PROMPT_ORDER).strip().lower()
+        if choice == COMMAND_OFF:
+            return
+        if choice == COMMAND_REPORT:
+            report(resources, profit)
+        elif choice in MENU:
+            drink = MENU[choice]
+            if not is_resource_sufficient(drink["ingredients"], resources):
+                continue
+            payment = process_coins()
+            if is_transaction_successful(payment, drink["cost"]):
+                profit += drink["cost"]
+                make_coffee(choice, drink["ingredients"], resources)
+        else:
+            print(MESSAGE_UNKNOWN_DRINK)

tests/__init__.py

@@ -0,0 +1,4 @@
+"""!
+@file __init__.py
+@brief Test package.
+"""

tests/conftest.py

@@ -0,0 +1,25 @@
+"""!
+@file conftest.py
+@brief Shared pytest helpers.
+"""
+
+from collections.abc import Callable, Iterable
+
+import pytest
+
+ScriptInput = Callable[[Iterable[str]], None]
+
+
+@pytest.fixture
+def script_input(monkeypatch: pytest.MonkeyPatch) -> ScriptInput:
+    """!
+    @brief Provide a function that feeds the given answers to `input`.
+    @param monkeypatch pytest's monkeypatch fixture.
+    @return A function taking the answers in the order they are asked.
+    """
+
+    def feed(answers: Iterable[str]) -> None:
+        remaining = iter(answers)
+        monkeypatch.setattr("builtins.input", lambda _prompt: next(remaining))
+
+    return feed

tests/test_machine.py

@@ -0,0 +1,107 @@
+"""!
+@file test_machine.py
+@brief Tests for making drinks and the main loop.
+"""
+
+import pytest
+
+from coffee_machine.constants import MENU
+from coffee_machine.main import main, make_coffee
+from tests.conftest import ScriptInput
+
+COINS_FOR_LATTE = ["10", "0", "0", "0"]
+NO_COINS = ["0", "0", "0", "0"]
+FULL_REPORT = "Water: 300ml\nMilk: 200ml\nCoffee: 100g\nMoney: $0.00"
+
+
+def test_make_coffee_uses_up_ingredients(capsys: pytest.CaptureFixture[str]) -> None:
+    """!
+    @brief The drink's ingredients are deducted and the drink is served.
+    """
+    resources = {"water": 300, "milk": 200, "coffee": 100}
+    make_coffee("latte", MENU["latte"]["ingredients"], resources)
+    assert resources == {"water": 100, "milk": 50, "coffee": 76}
+    assert capsys.readouterr().out == "Here is your latte. Enjoy!\n"
+
+
+def test_off_ends_the_machine(script_input: ScriptInput) -> None:
+    """!
+    @brief Typing off returns from the loop.
+    """
+    script_input(["off"])
+    main()
+
+
+def test_report_shows_starting_resources(
+    script_input: ScriptInput, capsys: pytest.CaptureFixture[str]
+) -> None:
+    """!
+    @brief A fresh machine reports full resources and no money.
+    """
+    script_input(["report", "off"])
+    main()
+    assert FULL_REPORT in capsys.readouterr().out
+
+
+def test_unknown_input_is_rejected(
+    script_input: ScriptInput, capsys: pytest.CaptureFixture[str]
+) -> None:
+    """!
+    @brief Anything that is not a drink or command prints a message.
+    """
+    script_input(["tea", "off"])
+    main()
+    assert "Sorry, we do not serve that." in capsys.readouterr().out
+
+
+def test_sale_updates_resources_and_profit(
+    script_input: ScriptInput, capsys: pytest.CaptureFixture[str]
+) -> None:
+    """!
+    @brief A paid drink is served, resources drop and profit rises by the price.
+    """
+    script_input(["latte", *COINS_FOR_LATTE, "report", "off"])
+    main()
+    out = capsys.readouterr().out
+    assert "Here is your latte. Enjoy!" in out
+    assert "Water: 100ml\nMilk: 50ml\nCoffee: 76g\nMoney: $2.50" in out
+
+
+def test_refund_changes_nothing(
+    script_input: ScriptInput, capsys: pytest.CaptureFixture[str]
+) -> None:
+    """!
+    @brief An underpaid order is refunded: no drink, no profit.
+    """
+    script_input(["espresso", *NO_COINS, "report", "off"])
+    main()
+    out = capsys.readouterr().out
+    assert "Money refunded." in out
+    assert "Enjoy" not in out
+    assert FULL_REPORT in out
+
+
+def test_overpayment_adds_only_price_to_profit(
+    script_input: ScriptInput, capsys: pytest.CaptureFixture[str]
+) -> None:
+    """!
+    @brief Change is returned and only the price is counted as profit.
+    """
+    script_input(["espresso", "7", "0", "0", "0", "report", "off"])
+    main()
+    out = capsys.readouterr().out
+    assert "Here is $0.25 in change." in out
+    assert "Money: $1.50" in out
+
+
+def test_order_refused_when_resources_run_out(
+    script_input: ScriptInput, capsys: pytest.CaptureFixture[str]
+) -> None:
+    """!
+    @brief After the water is used up, the next order is refused before payment.
+    """
+    script_input(["latte", *COINS_FOR_LATTE, "latte", "off"])
+    main()
+    out = capsys.readouterr().out
+    assert out.count("Please insert coins.") == 1
+    assert "Sorry there is not enough water." in out

tests/test_resources.py

@@ -0,0 +1,52 @@
+"""!
+@file test_resources.py
+@brief Tests for the report and the resource check.
+"""
+
+import pytest
+
+from coffee_machine.constants import INITIAL_RESOURCES, MENU
+from coffee_machine.main import format_money, is_resource_sufficient, report
+
+
+def test_format_money_shows_two_decimals() -> None:
+    """!
+    @brief Cents are shown as dollars with two decimals.
+    """
+    assert format_money(250) == "$2.50"
+    assert format_money(0) == "$0.00"
+
+
+def test_report_prints_resources_and_money(capsys: pytest.CaptureFixture[str]) -> None:
+    """!
+    @brief The report lists each resource with its unit, then the money.
+    """
+    report({"water": 300, "milk": 200, "coffee": 100}, 250)
+    assert capsys.readouterr().out == (
+        "Water: 300ml\nMilk: 200ml\nCoffee: 100g\nMoney: $2.50\n"
+    )
+
+
+def test_is_resource_sufficient_when_enough() -> None:
+    """!
+    @brief An order is accepted when every ingredient is available.
+    """
+    assert is_resource_sufficient(MENU["latte"]["ingredients"], INITIAL_RESOURCES)
+
+
+def test_is_resource_sufficient_when_exactly_enough() -> None:
+    """!
+    @brief Using up an ingredient completely is allowed.
+    """
+    assert is_resource_sufficient({"water": 300}, {"water": 300})
+
+
+def test_is_resource_sufficient_names_missing_resource(
+    capsys: pytest.CaptureFixture[str],
+) -> None:
+    """!
+    @brief A short ingredient is refused and named.
+    """
+    resources = {"water": 300, "milk": 100, "coffee": 100}
+    assert not is_resource_sufficient(MENU["latte"]["ingredients"], resources)
+    assert capsys.readouterr().out == "Sorry there is not enough milk.\n"

tests/test_smoke.py

@@ -3,11 +3,14 @@
 @brief Smoke test that the package imports.
 """
 
+import pytest
+
 from coffee_machine import main as main_module
 
 
-def test_main_is_callable() -> None:
+def test_main_is_callable(monkeypatch: pytest.MonkeyPatch) -> None:
     """!
-    @brief The entry point runs without error.
+    @brief The entry point starts and stops on "off".
     """
+    monkeypatch.setattr("builtins.input", lambda _prompt: "off")
     main_module.main()

tests/test_transactions.py

@@ -0,0 +1,56 @@
+"""!
+@file test_transactions.py
+@brief Tests for coin processing and payment.
+"""
+
+import pytest
+
+from coffee_machine.main import is_transaction_successful, process_coins
+from tests.conftest import ScriptInput
+
+
+def test_process_coins_totals_in_cents(script_input: ScriptInput) -> None:
+    """!
+    @brief Quarters, dimes, nickels and pennies add up to the right total.
+    """
+    script_input(["4", "3", "2", "1"])
+    assert process_coins() == 4 * 25 + 3 * 10 + 2 * 5 + 1
+
+
+def test_process_coins_asks_again_on_invalid_count(
+    script_input: ScriptInput, capsys: pytest.CaptureFixture[str]
+) -> None:
+    """!
+    @brief Text and negative counts are rejected and asked again.
+    """
+    script_input(["abc", "-1", "2", "0", "0", "0"])
+    assert process_coins() == 50
+    assert capsys.readouterr().out.count("Please enter a whole number") == 2
+
+
+def test_transaction_refused_when_too_little(
+    capsys: pytest.CaptureFixture[str],
+) -> None:
+    """!
+    @brief Too little money is refunded with the refund message.
+    """
+    assert not is_transaction_successful(100, 150)
+    assert "Sorry that's not enough money. Money refunded." in capsys.readouterr().out
+
+
+def test_transaction_accepted_with_exact_payment(
+    capsys: pytest.CaptureFixture[str],
+) -> None:
+    """!
+    @brief Exact payment succeeds and gives no change.
+    """
+    assert is_transaction_successful(150, 150)
+    assert "change" not in capsys.readouterr().out
+
+
+def test_transaction_gives_change(capsys: pytest.CaptureFixture[str]) -> None:
+    """!
+    @brief Overpaying succeeds and returns the difference.
+    """
+    assert is_transaction_successful(175, 150)
+    assert capsys.readouterr().out == "Here is $0.25 in change.\n"