code: def test_pylong_misbehavior_error_path_to_str(self, mock_int_to_str):
      with support.adjust_int_max_str_digits(20_000):
          big_value = int("7" * 19_999)
          mock_int_to_str.return_value = None  # not a str
          with self.assertRaises(TypeError) as ctx:
              str(big_value)
          self.assertIn(
              "_pylong.int_to_decimal_string did not",
              str(ctx.exception),
          )
          mock_int_to_str.side_effect = RuntimeError("testABC")
          with self.assertRaises(RuntimeError):
              str(big_value)
  
imports: import sys
  import time
  import unittest
  from unittest import mock
  from test import support
  from test.test_grammar import VALID_UNDERSCORE_LITERALS, INVALID_UNDERSCORE_LITERALS
label_desc: Use image node_id 6 for calling the PyLongModuleTests obj's underlying member method code with example usage: obj.test_pylong_misbehavior_error_path_to_str(mock_int_to_str) without return types