code: def test_base_cases():
      classes = (ADFTest, KPSSTest, PPTest)
      for cls in classes:
          instance = cls()
  
          # Also show we get a warning with the deprecated func
          with pytest.warns(DeprecationWarning):
              p_val, is_stationary = instance.is_stationary(None)
  
          # results of base-case
          assert np.isnan(p_val)
          assert not is_stationary
  
file_path: pmdarima/pmdarima/arima/tests/test_stationarity.py
imports: from pmdarima.arima.stationarity import ADFTest, PPTest, KPSSTest
  from pmdarima.arima.utils import ndiffs
  from pmdarima.utils.array import diff
  from pmdarima.datasets import load_austres
  from sklearn.utils import check_random_state
  from numpy.testing import assert_array_almost_equal, assert_almost_equal, assert_array_equal
  import numpy
  import pytest
label_desc: Use image node_id 12 for calling a global function with example usage: test_base_cases() without return types