code: def test_linear_extrapolation_endogenous_only(
      fh, window_length, strategy, method, slope, regressor, scitype
  ):
      """Test linear extrapolation endogenous only."""
      n_timepoints = 13
      y = _make_y(0, n_timepoints, method=method, slope=slope)
      y = pd.Series(y)
      fh = check_fh(fh)
  
      forecaster = make_reduction(
          regressor,
          scitype=scitype,
          window_length=window_length,
          strategy=strategy,
      )
      forecaster.fit(y, fh=fh)
      actual = forecaster.predict()
  
      end = n_timepoints + max(fh) + 1
      expected = _make_y(n_timepoints, end, method=method, slope=slope)[
          fh.to_indexer()
      ]
      np.testing.assert_almost_equal(actual, expected)
  
imports: import numpy
  import pandas
  import pytest
  from sklearn.base import BaseEstimator, RegressorMixin
  from sklearn.dummy import DummyRegressor
  from sklearn.linear_model import LinearRegression
  from sklearn.pipeline import make_pipeline
  from sktime.datasets import load_airline
  from sktime.forecasting.base import ForecastingHorizon
  from sktime.forecasting.compose import DirectTabularRegressionForecaster, DirectTimeSeriesRegressionForecaster, DirRecTabularRegressionForecaster, DirRecTimeSeriesRegressionForecaster, MultioutputTabularRegressionForecaster, MultioutputTimeSeriesRegressionForecaster, RecursiveTabularRegressionForecaster, RecursiveTimeSeriesRegressionForecaster, make_reduction
  from sktime.forecasting.compose._reduce import _sliding_window_transform
  from sktime.forecasting.tests._config import TEST_OOS_FHS, TEST_WINDOW_LENGTHS_INT
  from sktime.performance_metrics.forecasting import mean_absolute_percentage_error
  from sktime.regression.base import BaseRegressor
  from sktime.regression.interval_based import TimeSeriesForestRegressor
  from sktime.split import SlidingWindowSplitter, temporal_train_test_split
  from sktime.split.tests.test_split import _get_windows
  from sktime.transformations.panel.reduce import Tabularizer
  from sktime.utils._testing.forecasting import make_forecasting_problem
  from sktime.utils.validation.forecasting import check_fh
label_desc: Use image node_id 7 for calling a global function with example usage: test_linear_extrapolation_endogenous_only(fh, window_length, strategy, method, slope, regressor, scitype) without return types