def METHOD_NAME(self):
    self.render_resource(self.sse, b'/listen')
    request = self.request
    self.readUUID(request)
    self.render_resource(self.sse, b'/add/foo')
    self.assertEqual(self.request.finished, True)
    self.assertEqual(self.request.responseCode, 400)
    self.assertIn(b"unknown uuid", self.request.written)