def METHOD_NAME(self):
    patched_client = MagicMock()
    patched_client.execute_command.return_value = self._pull_messages(1)
    processor = MailerGcpQueueProcessor(MAILER_CONFIG_GCP, logger)
    processor.client = patched_client
    messages = processor.receive_messages()
    self.assertEqual(len(messages["receivedMessages"]), 1)
    patched_client.execute_command.assert_called_with(
        "pull",
        {
            "subscription": "projects/c7n-dev/subscriptions/getnotify",
            "body": {"returnImmediately": True, "max_messages": 1000},
        },
    )