def METHOD_NAME(
    coord_dtype: np.dtype, lazy: bool, with_bounds: bool
) -> None:
    """Test extent calculation of scalar dimension coordinates."""
    metadata = create_metadata(
        dim_coord=True,
        scalar=True,
        order=_CONSTANT,
        coord_dtype=coord_dtype,
        lazy=lazy,
        with_bounds=with_bounds,
    )
    dim_metadata = [_CoordMetaData(metadata.coord, metadata.dims)]
    cube_signature = MockCubeSignature(
        dim_coords=[metadata.coord], dim_metadata=dim_metadata
    )
    coord_signature = _CoordSignature(cube_signature)
    assert len(coord_signature.dim_extents) == 1
    (actual,) = coord_signature.dim_extents
    point = coord_dtype(1)
    points_extent = _Extent(min=point, max=point)
    bounds_extent = None
    if with_bounds:
        first, last = coord_dtype(0), coord_dtype(2)
        bounds_extent = (
            _Extent(min=first, max=first),
            _Extent(min=last, max=last),
        )
    expected = _CoordExtent(points=points_extent, bounds=bounds_extent)
    assert actual == expected