def METHOD_NAME(self):
    mask = np.zeros((6, 6), dtype=np.uint8)
    mask[1:-1, 1:-1] = 1
    nm_scalar = UNIT_SCALE[Units.nm.value]
    voxel_size = (1 / nm_scalar,) * 2
    result_mask = BorderRim.border_mask(mask, 1, Units.nm, voxel_size)
    mask2 = np.copy(mask)
    mask2[2:-2, 2:-2] = 0
    assert np.all(mask2 == result_mask)