code: def test_failure_cases(self):
      A, B, C, D = self.data()
  
      match = r".*Got blocks\[{}\]\.shape\[{}\] == 1, expected 2"
  
      # test failure cases
      message1 = re.compile(match.format("1,0", "1"))
      with pytest.raises(ValueError, match=message1):
          _construct.bmat([[A], [B]], dtype=self.dtype)
  
      message2 = re.compile(match.format("0,1", "0"))
      with pytest.raises(ValueError, match=message2):
          _construct.bmat([[A, C]], dtype=self.dtype)
  
imports: import functools
  import re
  from unittest import mock
  import numpy
  import pytest
  import cupy
  from cupy import testing
  from cupy.cuda import runtime
  from cupyx.scipy import sparse
  from cupyx.scipy.sparse import _construct
label_desc: Use image node_id 5 for calling the TestBmat obj's underlying member method code with example usage: obj.test_failure_cases() without return types