def test_shift(self):
        shifted = self.ts.shift(1)
        unshifted = shifted.shift(-1)

        tm.assert_dict_equal(unshifted.valid(), self.ts, compare_keys=False)

        offset = datetools.bday
        shifted = self.ts.shift(1, freq=offset)
        unshifted = shifted.shift(-1, freq=offset)

        assert_series_equal(unshifted, self.ts)

        unshifted = self.ts.shift(0, freq=offset)
        assert_series_equal(unshifted, self.ts)

        shifted = self.ts.shift(1, freq='B')
        unshifted = shifted.shift(-1, freq='B')

        assert_series_equal(unshifted, self.ts)

        # corner case
        unshifted = self.ts.shift(0)
        assert_series_equal(unshifted, self.ts)

        # Shifting with PeriodIndex
        ps = tm.makePeriodSeries()
        shifted = ps.shift(1)
        unshifted = shifted.shift(-1)
        tm.assert_dict_equal(unshifted.valid(), ps, compare_keys=False)

        shifted2 = ps.shift(1, 'B')
        shifted3 = ps.shift(1, datetools.bday)
        assert_series_equal(shifted2, shifted3)
        assert_series_equal(ps, shifted2.shift(-1, 'B'))

        self.assertRaises(ValueError, ps.shift, freq='D')

        # legacy support
        shifted4 = ps.shift(1, freq='B')
        assert_series_equal(shifted2, shifted4)

        shifted5 = ps.shift(1, freq=datetools.bday)
        assert_series_equal(shifted5, shifted4)

        # 32-bit taking
        # GH 8129
        index = date_range('2000-01-01', periods=5)
        for dtype in ['int32', 'int64']:
            s1 = Series(np.arange(5, dtype=dtype), index=index)
            p = s1.iloc[1]
            result = s1.shift(periods=p)
            expected = Series([np.nan, 0, 1, 2, 3], index=index)
            assert_series_equal(result, expected)

        # xref 8260
        # with tz
        s = Series(
            date_range('2000-01-01 09:00:00', periods=5,
                       tz='US/Eastern'), name='foo')
        result = s - s.shift()
        assert_series_equal(result, Series(
            TimedeltaIndex(['NaT'] + ['1 days'] * 4), name='foo'))

        # incompat tz
        s2 = Series(
            date_range('2000-01-01 09:00:00', periods=5, tz='CET'), name='foo')
        self.assertRaises(ValueError, lambda: s % s2)
dataset/ETHPy150Open pydata/pandas/pandas/tests/series/test_timeseries.py/TestSeriesTimeSeries.test_shift/operator `-` -> `%`