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问Python asyncio:如何模拟aiter()方法？
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Stack Overflow用户

提问于 2016-04-18 21:22:31

回答 4查看 8.9K关注 0票数 8

我有一个使用aiohttp在WebSocket上监听消息的代码。

看起来是这样的：

async for msg in ws:
    await self._ws_msg_handler.handle_message(ws, msg, _services)

其中ws是aiohttp.web.WebSocketResponse() (original code)的实例

在我的测试中，我模拟了WebSocketResponse()及其__aiter__方法：

def coro_mock(**kwargs):
    return asyncio.coroutine(mock.Mock(**kwargs))


@pytest.mark.asyncio
@mock.patch('aiojsonrpc.request_handler.WebSocketMessageHandler')
async def test_rpc_websocket_handler(
    MockWebSocketMessageHandler,
    rpc_websocket_handler
):

    ws_response = 'aiojsonrpc.request_handler.WebSocketResponse'
    with mock.patch(ws_response) as MockWebSocketResponse:
        MockRequest = mock.MagicMock()
        req = MockRequest()

        ws_instance = MockWebSocketResponse.return_value
        ws_instance.prepare = coro_mock()
        ws_instance.__aiter__ = coro_mock(return_value=iter(range(5)))
        ws_instance.__anext__ = coro_mock()

        handle_msg_result = 'Message processed'
        MockWebSocketMessageHandler.handle_message.side_effect = Exception(
            handle_msg_result)
        msg_handler = MockWebSocketMessageHandler()

        with pytest.raises(Exception) as e:
            await request_handler.RpcWebsocketHandler(msg_handler)(req)
        assert str(e.value) == handle_msg_result

不过，当我运行test时，它会失败，并显示以下错误消息：

“async for”需要具有__aiter__方法的对象，已获取MagicMock

=================================================================================== FAILURES ===================================================================================
__________________________________________________________________________ test_rpc_websocket_handler __________________________________________________________________________

MockWebSocketMessageHandler = <MagicMock name='WebSocketMessageHandler' id='140687969989632'>
rpc_websocket_handler = <aiojsonrpc.request_handler.RpcWebsocketHandler object at 0x7ff47879b0f0>

    @pytest.mark.asyncio
    @mock.patch('aiojsonrpc.request_handler.WebSocketMessageHandler')
    async def test_rpc_websocket_handler(
        MockWebSocketMessageHandler,
        rpc_websocket_handler
    ):

        ws_response = 'aiojsonrpc.request_handler.WebSocketResponse'
        with mock.patch(ws_response) as MockWebSocketResponse:
            # MockRequest = mock.create_autospec(aiohttp.web_reqrep.Request)
            # req = MockRequest(*[None] * 6)
            MockRequest = mock.MagicMock()
            req = MockRequest()

            ws_instance = MockWebSocketResponse.return_value
            ret = mock.Mock()
            ws_instance.prepare = coro_mock()
            ws_instance.__aiter__ = coro_mock(return_value=iter(range(5)))
            ws_instance.__anext__ = coro_mock()

            handle_msg_result = 'Message processed'
            MockWebSocketMessageHandler.handle_message.side_effect = Exception(
                handle_msg_result)
            msg_handler = MockWebSocketMessageHandler()

            with pytest.raises(Exception) as e:
                await request_handler.RpcWebsocketHandler(msg_handler)(req)
>           assert str(e.value) == handle_msg_result
E           assert "'async for' ...got MagicMock" == 'Message processed'
E             - 'async for' requires an object with __aiter__ method, got MagicMock
E             + Message processed

tests/test_request_handler.py:252: AssertionError

所以它的表现就像__aiter__()从来没有被嘲笑过一样。在这种情况下，我应该如何完成正确的模仿？

更新：

目前，我已经找到了一个workaround来使代码可测试，但如果有人告诉我如何处理原始问题中描述的问题，我会非常感激。

python-3.x

pytest

python-asyncio

aiohttp

python-unittest.mock

页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持

原文链接：

https://stackoverflow.com/questions/36695256

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