def test_can_create_year():
year = GregorianCalendar.Date(2000)
assert year.year == 2000
assert year.month is None
assert year.day is None
assert str(year) == "2000"
def test_can_create_date_with_short_numbers():
date = GregorianCalendar.Date(2000, 1, 2)
assert date.year == 2000
assert date.month == 1
assert date.day == 2
assert str(date) == "2000-01-02"
def test_can_create_month_year():
month_year = GregorianCalendar.Date(2000, 12)
assert month_year.year == 2000
assert month_year.month == 12
assert month_year.day is None
assert str(month_year) == "2000-12"
def test_can_create_date():
date = GregorianCalendar.Date(2000, 12, 25)
assert date.year == 2000
assert date.month == 12
assert date.day == 25
assert str(date) == "2000-12-25"
