code: def testPrintMessageSetAsOneLine(self):
      message = unittest_mset_pb2.TestMessageSetContainer()
      ext1 = (
          unittest_mset_pb2.TestMessageSetExtension1.message_set_extension
      )
      ext2 = (
          unittest_mset_pb2.TestMessageSetExtension2.message_set_extension
      )
      message.message_set.Extensions[ext1].i = 23
      message.message_set.Extensions[ext2].str = "foo"
      self.CompareToGoldenText(
          text_format.MessageToString(message, as_one_line=True),
          "message_set {"
          " [protobuf_unittest.TestMessageSetExtension1] {"
          " i: 23"
          " }"
          " [protobuf_unittest.TestMessageSetExtension2] {"
          ' str: "foo"'
          " }"
          " }",
      )
  
imports: import difflib
  import re
  import unittest
  from google.protobuf import text_format
  from google.protobuf.internal import test_util
  from google.protobuf import unittest_pb2
  from google.protobuf import unittest_mset_pb2
label_desc: Use image node_id 12 for calling the TextFormatTest obj's underlying member method code with example usage: obj.testPrintMessageSetAsOneLine() without return types