def METHOD_NAME(posaveraging_universes):
    '''
    Test if the position averaging function is returning the correct
    values when iterating backwards over the trajectory.
    '''
    ref_matrix_bwd = np.asarray([10., 10., 10.])
    size = (posaveraging_universes.trajectory.ts.positions.shape[0], 
            posaveraging_universes.trajectory.ts.positions.shape[1], 
            len(posaveraging_universes.trajectory))
    back_avgd = np.empty(size)
    for ts in posaveraging_universes.trajectory[::-1]:
        back_avgd[...,9-ts.frame] = ts.positions.copy()
    assert_array_almost_equal(ref_matrix_bwd, back_avgd[1,:,-1], decimal=5)