docstr: If there is no statements in the database, then the
  user's input is the only thing that can be returned.
docstr_tok: ["If","there","is","no","statements","in","the","database",",","then","the","user","'s","input","is","the","only","thing","that","can","be","returned","."]
code: def test_no_statements_known(self):
      """
      If there is no statements in the database, then the
      user's input is the only thing that can be returned.
      """
      statement_text = "How are you?"
      response = self.chatbot.get_response(statement_text)
      results = list(self.chatbot.storage.filter(text=statement_text))
  
      self.assertEqual(response.text, statement_text)
      self.assertEqual(response.confidence, 0)
  
      # Make sure that the input and output were saved
      self.assertIsLength(results, 2)
      self.assertEqual(results[0].text, statement_text)
      self.assertEqual(results[1].text, statement_text)
  
imports: from tests.base_case import ChatBotTestCase
  from chatterbot.logic import LogicAdapter
  from chatterbot.conversation import Statement
label_desc: Use image node_id 4 for calling the ChatterBotResponseTestCase obj's underlying member method code with example usage: obj.test_no_statements_known() without return types