code: def test_recursive_predict_output_when_regressor_is_LinearRegression():
      """
      Test _recursive_predict output when using LinearRegression as regressor.
      """
      forecaster = ForecasterAutoregCustom(
          regressor=LinearRegression(),
          fun_predictors=create_predictors,
          window_size=5,
      )
      forecaster.fit(y=pd.Series(np.arange(50)))
      predictions = forecaster._recursive_predict(
          steps=5, last_window=forecaster.last_window.values, exog=None
      )
      expected = np.array([50.0, 51.0, 52.0, 53.0, 54.0])
  
      assert predictions == approx(expected)
  
file_path: skforecast/skforecast/ForecasterAutoregCustom/tests/test_recursive_predict.py
imports: from pytest import approx
  import pytest
  import re
  import numpy
  import pandas
  from skforecast.ForecasterAutoregCustom import ForecasterAutoregCustom
  from sklearn.linear_model import LinearRegression
label_desc: Use image node_id 3 for calling a global function with example usage: test_recursive_predict_output_when_regressor_is_LinearRegression() without return types