def test_shifted_low_freq_anchor(self):
        """
        Check that values are properly extracted when the beginning of the series is not aligned with the low
        frequency anchor value (day of the week).
        """
        ts = linear_timeseries(
            start=pd.Timestamp("2000-01-01"),
            freq="D",
            start_value=1,
            end_value=22,
            length=22,
        )
        assert ts.time_index[2].day_name() == "Monday"

        midas_mon = MIDAS(low_freq="W-MON", strip=False)
        ts_monday_anchor = midas_mon.fit_transform(ts)
        # the resampled series start at the previous anchor point (incomplete)
        assert ts_monday_anchor.time_index[0] == pd.Timestamp("2000-01-03")
        assert ts_monday_anchor.freq == "W-MON"
        assert len(ts_monday_anchor) == 4
        # incomplete low frequency period
        assert (
            ts_monday_anchor[0].values().flatten()[-3:] == ts[:3].values().flatten()
        ).all()
        # complete low frequency period
        assert (
            ts_monday_anchor[1].values().flatten() == ts[3:10].values().flatten()
        ).all()

        # reverse transform
        ts_inv_monday_anchor = midas_mon.inverse_transform(ts_monday_anchor)
        np.testing.assert_array_almost_equal(ts.values(), ts_inv_monday_anchor.values())
        assert ts.time_index.equals(ts_inv_monday_anchor.time_index)

        # with strip, it skips first and last week
        midas_mon = MIDAS(low_freq="W-MON", strip=True)
        ts_monday_anchor = midas_mon.fit_transform(ts)
        assert ts_monday_anchor.time_index[0] == pd.Timestamp("2000-01-10")
        assert ts_monday_anchor.freq == "W-MON"
        assert len(ts_monday_anchor) == 2
        # first complete low frequency period
        assert (
            ts_monday_anchor[0].values().flatten() == ts[3:10].values().flatten()
        ).all()

        Check that values are properly extracted when the beginning of the series is not aligned with the low
        frequency anchor value (day of the week).
        
darts/tests/dataprocessing/transformers/test_midas.py