code: def test_corner():
      # fails because lag < 1
      with pytest.raises(ValueError):
          diff(x=x, lag=0)
      with pytest.raises(ValueError):
          diff_inv(x=x, lag=0)
  
      # fails because differences < 1
      with pytest.raises(ValueError):
          diff(x=x, differences=0)
      with pytest.raises(ValueError):
          diff_inv(x=x, differences=0)
  
      # Passing in xi with the incorrect shape to a 2-d array
      with pytest.raises(IndexError):
          diff_inv(x=np.array([[1, 1], [1, 1]]), xi=np.array([[1]]))
  
imports: from pmdarima.utils.array import diff, diff_inv, c, is_iterable, as_series, check_exog, check_endog
  from pmdarima.utils import get_callable
  from numpy.testing import assert_array_equal, assert_array_almost_equal
  import datetime
  import pytest
  import pandas
  import numpy
label_desc: Use image node_id 7 for calling a global function with example usage: test_corner() without return types