docstr: Tests respond() when it errors out.
docstr_tok: ["Tests","respond","(",")","when","it","errors","out","."]
code: def test_respond_error(self):
      """
      Tests respond() when it errors out.
      """
      agent = create_agent(dict(model="repeat_query"))
      error_message = "The agent needs a 'text' field in the message."
      with self.assertRaises(Exception) as context:
          agent.respond(Message(episode_done=True))
      self.assertEqual(str(context.exception), error_message)
      with self.assertRaises(Exception) as context:
          agent.respond({})
      self.assertEqual(str(context.exception), error_message)
      with self.assertRaises(Exception) as context:
          agent.respond(Message())
      self.assertEqual(str(context.exception), error_message)
  
file_path: ParlAI/tests/test_repeat_query_agent.py
imports: import unittest
  from parlai.core.agents import create_agent
  from parlai.core.message import Message
label_desc: Use image node_id 2 for calling the TestRepeatQueryAgent obj's underlying member method code with example usage: obj.test_respond_error() without return types