def test_calibration_hfc_start_position_hist_fc(self, config):
        """Test calibration historical forecast start point when calling `historical_forecasts()`
        with start format "position"."""
        cal_length, cal_stride, start, start_expected = config
        series = linear_timeseries(length=4)
        horizon = 2
        output_chunk_shift = 1
        assert _get_calibration_hfc_start(
            series=[series],
            horizon=horizon,
            output_chunk_shift=output_chunk_shift,
            cal_length=cal_length,
            cal_stride=cal_stride,
            start=start,
            start_format="position",
        ) == (start_expected, "position")
Test calibration historical forecast start point when calling `historical_forecasts()`
        with start format "position".
darts/tests/models/forecasting/test_conformal_model.py