code: def test_boundary_error_message(self):
      regex1 = (
          r"pack_into requires a buffer of at least 6 "
          r"bytes for packing 1 bytes at offset 5 "
          r"\(actual buffer size is 1\)"
      )
      with self.assertRaisesRegex(struct.error, regex1):
          struct.pack_into("b", bytearray(1), 5, 1)
  
      regex2 = (
          r"unpack_from requires a buffer of at least 6 "
          r"bytes for unpacking 1 bytes at offset 5 "
          r"\(actual buffer size is 1\)"
      )
      with self.assertRaisesRegex(struct.error, regex2):
          struct.unpack_from("b", bytearray(1), 5)
  
imports: from collections import abc
  import array
  import gc
  import math
  import operator
  import unittest
  import struct
  import sys
  import weakref
  from test import support
  from test.support import import_helper
  from test.support.script_helper import assert_python_ok
label_desc: Use image node_id 21 for calling the StructTest obj's underlying member method code with example usage: obj.test_boundary_error_message() without return types