code: def test_ocsb_regression():
      # fitOCSB is a closure function inside of forecast::ocsb.test
      # > fitOCSB(austres, 1, 1)
      # Coefficients:
      # xregmf.x    xregZ4    xregZ5
      #   0.2169    0.2111   -0.8625
  
      # We get different results here, but only marginally...
      reg = OCSBTest._fit_ocsb(austres, m=4, lag=1, max_lag=1)
      coef = reg.params
      assert np.allclose(coef, [0.2169, 0.2111, -0.8625], rtol=0.01)
  
imports: from pmdarima.arima.seasonality import CHTest, decompose, OCSBTest
  from pmdarima.arima.utils import nsdiffs
  from pmdarima.compat.pytest import pytest_error_str
  from pmdarima.datasets import load_airpassengers, load_ausbeer, load_austres, load_wineind
  import numpy
  from numpy.testing import assert_almost_equal, assert_array_equal
  from sklearn.utils.validation import check_random_state
  import pytest
  from unittest import mock
label_desc: Use image node_id 12 for calling a global function with example usage: test_ocsb_regression() without return types