code: def test_handle_message_ready_reply(self):
      def assert_ready(msg=None, metadata=None):
          self.assertEqual(
              metadata, {"msg_type": "Ready", "content": ""}
          )
  
      comm = Comm(id="Test")
      comm.send = assert_ready
      comm._handle_msg({})
  
file_path: holoviews/holoviews/tests/plotting/test_comms.py
imports: from pyviz_comms import Comm, JupyterComm
  from holoviews.element.comparison import ComparisonTestCase
label_desc: Use image node_id 5 for calling the TestComm obj's underlying member method code with example usage: obj.test_handle_message_ready_reply() without return types