import pytest

from src.exercises.pricing import discount_price


def test_discount_price_happy_path():
    result = discount_price(100.0, 20.0)
    assert result == 80.0


def test_discount_price_edge_case_1():
    result = discount_price(100.0, 100.0)
    assert result == 0.0


def test_discount_price_edge_case_2():
    result = discount_price(100.0, 0.0)
    assert result == 100.0


def test_discount_price_negative_price():
    with pytest.raises(ValueError, match="price cannot be negative"):
        discount_price(-1.0, 20.0)


def test_discount_price_invalid_discount():
    with pytest.raises(ValueError, match="discount must be between 0 and 100"):
        discount_price(100.0, 120.0)