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
    """
    pSpill = sample_sc_release(num_le, start_pos, rel_time)
    curr = CurrentCycleMover(curr_file, topology_file, tide=td)
    delta = _certain_loop(pSpill, curr)
    _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
    assert np.all(delta[:, 2] == 0)  # 'z' is zeros