import datetime
import dates
from dates import Precision

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)

def test_resolve_feast_movable():
    assert dates.resolve_feast_or_season("Pfingsten", 1922) == ("1922-06-04", Precision.DAY)
    assert dates.resolve_feast_or_season("Ostern", 2024) == ("2024-03-31", Precision.DAY)
    assert dates.resolve_feast_or_season("Pfingstmontag", 1922) == ("1922-06-05", Precision.DAY)

def test_resolve_feast_fixed():
    assert dates.resolve_feast_or_season("Weihnachten", 1900) == ("1900-12-25", Precision.DAY)
    assert dates.resolve_feast_or_season("Neujahr", 1910) == ("1910-01-01", Precision.DAY)

def test_resolve_season():
    assert dates.resolve_feast_or_season("Herbst", 1913) == ("1913-10-01", Precision.SEASON)
    assert dates.resolve_feast_or_season("Sommer", 1910) == ("1910-07-01", Precision.SEASON)

def test_resolve_unknown_token_returns_none():
    assert dates.resolve_feast_or_season("Freitag", 1919) is None

def test_expand_year():
    assert dates.expand_year("1888") == 1888
    assert dates.expand_year("889") == 1889      # 3-digit -> 1DDD
    assert dates.expand_year("923") == 1923
    assert dates.expand_year("08") == 1908       # 00..57 -> 19xx
    assert dates.expand_year("17") == 1917
    assert dates.expand_year("57") == 1957
    assert dates.expand_year("73") == 1873       # 73..99 -> 18xx
    assert dates.expand_year("99") == 1899
    assert dates.expand_year("65") is None       # 58..72 ambiguous
    assert dates.expand_year("x") is None