code: def test_get_response_missing_text(self):
      with self.assertRaises(self.chatbot.ChatBotException):
          self.chatbot.get_response()
  
imports: from tests.base_case import ChatBotTestCase
  from chatterbot.logic import LogicAdapter
  from chatterbot.conversation import Statement
label_desc: Use image node_id 20 for calling the ChatterBotResponseTestCase obj's underlying member method code with example usage: obj.test_get_response_missing_text() without return types