'Initialize the mock Comment Service server instance.
*port_num* is the localhost port to listen to
*response* is a dictionary that will be JSON-serialized
and sent in response to comment service requests.'

def __init__(self, port_num, response={'username': 'new', 'external_id': 1}):

    self._response_str = json.dumps(response)
    handler = MockCommentServiceRequestHandler
    address = ('', port_num)
    HTTPServer.__init__(self, address, handler)
