from datetime import date

import pytest
from app.services.purchase_orders import calendar_year_window


@pytest.mark.parametrize(
    ("as_of", "expected"),
    [
        (date(2026, 9, 10), (date(2023, 1, 1), date(2026, 12, 31))),
        (date(2025, 1, 1), (date(2022, 1, 1), date(2025, 12, 31))),
    ],
)
def test_three_year_window_uses_calendar_years(as_of: date, expected: tuple[date, date]) -> None:
    assert calendar_year_window(as_of, 3) == expected