def METHOD_NAME():
    """
    simplest possible -- the all water map
    """
    # this should now work like a regular map
    tfm = TideflatMap(get_gnomemap(), None)
    # a few things to make sure they work:
    assert tfm.on_map((11, 11, 0))
    assert not tfm.on_map((16, 16, 0))
    assert tfm.in_water((11, 11, 0))
    assert tfm.allowable_spill_position((13, 13, 0))
    assert not tfm.allowable_spill_position((10.5, 10.5, 0))