import datetime
import dates

def test_easter_known_years():
    # Anonymous Gregorian algorithm — verified against published tables
    assert dates.easter(2024) == datetime.date(2024, 3, 31)
    assert dates.easter(2000) == datetime.date(2000, 4, 23)
    assert dates.easter(1922) == datetime.date(1922, 4, 16)
    assert dates.easter(1888) == datetime.date(1888, 4, 1)