def METHOD_NAME():
    """
    test one time step with no uncertainty on the spill
    - checks there is non-zero motion.
    - also checks the motion is same for all LEs
    - Uncertainty needs to be off.
    - Windage needs to be set to not vary or each particle will have a
      different position,  This is done by setting the windage range to have
      all the same values (min == max).
    """
    pSpill = sample_sc_release(num_elements=num_le,
                               start_pos=start_pos,
                               release_time=rel_time,
                               windage_range=(0.01, 0.01))
    wind = c_GridWindMover(wind_file, topology_file)
    delta = _certain_loop(pSpill, wind)
    _assert_move(delta)
    assert np.all(delta[:, 0] == delta[0, 0])  # lat move matches for all LEs
    assert np.all(delta[:, 1] == delta[0, 1])  # long move matches for all LEs