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_money_machine.py

@@ -0,0 +1,62 @@
+"""! @file
+@brief Tests for MoneyMachine.
+"""
+
+import pytest
+
+from coffee_machine.money_machine import MoneyMachine
+from tests.conftest import InputFeeder
+
+
+def test_report_prints_profit(capsys: pytest.CaptureFixture[str]) -> None:
+    MoneyMachine().report()
+
+    assert capsys.readouterr().out == "Money: $0.00\n"
+
+
+def test_process_coins_adds_up_coin_values(feed_input: InputFeeder) -> None:
+    feed_input(["1", "2", "3", "4"])  # quarters, dimes, nickels, pennies
+
+    assert MoneyMachine().process_coins() == pytest.approx(0.64)
+
+
+def test_process_coins_asks_again_on_invalid_count(
+    feed_input: InputFeeder, capsys: pytest.CaptureFixture[str]
+) -> None:
+    feed_input(["abc", "-1", "4", "0", "0", "0"])
+
+    assert MoneyMachine().process_coins() == pytest.approx(1.0)
+    assert capsys.readouterr().out.count("whole number") == 2
+
+
+def test_make_payment_with_exact_amount_keeps_profit(
+    feed_input: InputFeeder, capsys: pytest.CaptureFixture[str]
+) -> None:
+    feed_input(["6", "0", "0", "0"])  # $1.50
+    machine = MoneyMachine()
+
+    assert machine.make_payment(1.5)
+    assert machine.profit == pytest.approx(1.5)
+    assert "change" not in capsys.readouterr().out
+
+
+def test_make_payment_with_excess_gives_change(
+    feed_input: InputFeeder, capsys: pytest.CaptureFixture[str]
+) -> None:
+    feed_input(["12", "0", "0", "0"])  # $3.00 for a $2.50 drink
+    machine = MoneyMachine()
+
+    assert machine.make_payment(2.5)
+    assert machine.profit == pytest.approx(2.5)
+    assert "$0.50 in change" in capsys.readouterr().out
+
+
+def test_make_payment_when_short_refunds_and_keeps_no_profit(
+    feed_input: InputFeeder, capsys: pytest.CaptureFixture[str]
+) -> None:
+    feed_input(["1", "0", "0", "0"])
+    machine = MoneyMachine()
+
+    assert not machine.make_payment(1.5)
+    assert machine.profit == 0.0
+    assert "Money refunded" in capsys.readouterr().out