Implement coffee machine program and tests (MIL-002)

Add the Menu, MenuItem, CoffeeMaker and MoneyMachine classes with the
assignment's method names, and a main loop that supports drink names,
report and off. Resources are checked before payment, and payment
before the drink is made.

Move drink prices, ingredient amounts and all message text into
constants.py. Add 25 pytest tests for every class and the main loop,
and record the review against QC-PY-001 as RC-007.

Task: MIL-002#1
Task: MIL-002#2
Task: MIL-002#3
Task: MIL-002#4
Task: MIL-002#5
Task: MIL-002#6
Closes #6
Closes #7
Closes #8
Closes #9
Closes #10
Closes #11

tests/test_coffee_maker.py

@@ -0,0 +1,68 @@
+"""! @file
+@brief Tests for CoffeeMaker.
+"""
+
+import pytest
+
+from coffee_machine import constants
+from coffee_machine.coffee_maker import CoffeeMaker
+from coffee_machine.menu import Menu, MenuItem
+
+
+def _drink(name: str) -> MenuItem:
+    drink = Menu().find_drink(name)
+    assert drink is not None
+    return drink
+
+
+def test_report_prints_each_resource_with_unit(
+    capsys: pytest.CaptureFixture[str],
+) -> None:
+    CoffeeMaker().report()
+
+    assert capsys.readouterr().out.splitlines() == [
+        "Water: 300ml",
+        "Milk: 200ml",
+        "Coffee: 100g",
+    ]
+
+
+def test_is_resource_sufficient_when_enough() -> None:
+    assert CoffeeMaker().is_resource_sufficient(_drink("latte"))
+
+
+def test_is_resource_sufficient_when_exactly_enough() -> None:
+    maker = CoffeeMaker()
+    maker.resources.update(
+        {constants.WATER: 50, constants.MILK: 0, constants.COFFEE: 18}
+    )
+
+    assert maker.is_resource_sufficient(_drink("espresso"))
+
+
+def test_is_resource_sufficient_when_short_names_each_missing_ingredient(
+    capsys: pytest.CaptureFixture[str],
+) -> None:
+    maker = CoffeeMaker()
+    maker.resources.update({constants.WATER: 10, constants.MILK: 10})
+
+    assert not maker.is_resource_sufficient(_drink("latte"))
+    out = capsys.readouterr().out
+    assert "not enough water" in out
+    assert "not enough milk" in out
+    assert "not enough coffee" not in out
+
+
+def test_make_coffee_deducts_ingredients_and_serves(
+    capsys: pytest.CaptureFixture[str],
+) -> None:
+    maker = CoffeeMaker()
+
+    maker.make_coffee(_drink("latte"))
+
+    assert maker.resources == {
+        constants.WATER: 100,
+        constants.MILK: 50,
+        constants.COFFEE: 76,
+    }
+    assert "latte" in capsys.readouterr().out