example-code-2e/10-dp-1class-func/classic_strategy_test.py

from decimal import Decimal

import pytest  # type: ignore

from classic_strategy import Customer, LineItem, Order
from classic_strategy import FidelityPromo, BulkItemPromo, LargeOrderPromo


@pytest.fixture
def customer_fidelity_0() -> Customer:
    return Customer('John Doe', 0)


@pytest.fixture
def customer_fidelity_1100() -> Customer:
    return Customer('Ann Smith', 1100)


@pytest.fixture
def cart_plain() -> tuple[LineItem, ...]:
    return (
        LineItem('banana', 4, Decimal('0.5')),
        LineItem('apple', 10, Decimal('1.5')),
        LineItem('watermelon', 5, Decimal('5.0')),
    )


def test_fidelity_promo_no_discount(customer_fidelity_0, cart_plain) -> None:
    order = Order(customer_fidelity_0, cart_plain, FidelityPromo())
    assert order.total() == 42
    assert order.due() == 42


def test_fidelity_promo_with_discount(customer_fidelity_1100, cart_plain) -> None:
    order = Order(customer_fidelity_1100, cart_plain, FidelityPromo())
    assert order.total() == 42
    assert order.due() == Decimal('39.9')


def test_bulk_item_promo_no_discount(customer_fidelity_0, cart_plain) -> None:
    order = Order(customer_fidelity_0, cart_plain, BulkItemPromo())
    assert order.total() == 42
    assert order.due() == 42


def test_bulk_item_promo_with_discount(customer_fidelity_0) -> None:
    cart = [LineItem('banana', 30, Decimal('0.5')),
            LineItem('apple', 10, Decimal('1.5'))]
    order = Order(customer_fidelity_0, cart, BulkItemPromo())
    assert order.total() == 30
    assert order.due() == Decimal('28.5')


def test_large_order_promo_no_discount(customer_fidelity_0, cart_plain) -> None:
    order = Order(customer_fidelity_0, cart_plain, LargeOrderPromo())
    assert order.total() == 42
    assert order.due() == 42


def test_large_order_promo_with_discount(customer_fidelity_0) -> None:
    cart = [LineItem(str(item_code), 1, Decimal(1))
            for item_code in range(10)]
    order = Order(customer_fidelity_0, cart, LargeOrderPromo())
    assert order.total() == 10
    assert order.due() == Decimal('9.3')