def METHOD_NAME(null):
    test = KPSSTest(alpha=0.05, null=null, lshort=True)
    pval, do_diff = test.should_diff(austres)
    assert do_diff  # show it is significant
    assert_almost_equal(pval, 0.01)
    # Test on the data provided in issue #67
    x = np.array([1, -1, 0, 2, -1, -2, 3])
    pval2, do_diff2 = test.should_diff(x)
    # We expect Trend to be significant, but NOT Level
    if null == 'level':
        assert not do_diff2
        assert_almost_equal(pval2, 0.1)
    else:
        assert do_diff2
        assert_almost_equal(pval2, 0.01)
    # test the ndiffs with the KPSS test
    assert ndiffs(austres, test='kpss', max_d=5, null=null) == 2