def test_arg_parse_error(args):
    """Helper function raises exception as expected"""
    with pytest.raises(mercantile.TileArgParsingError):
        mercantile._parse_tile_arg(*args)
def test_arg_parse(args, tile):
    """Helper function parse tile args properly"""
    assert mercantile._parse_tile_arg(*args) == mercantile.Tile(*tile)