Python-单元测试补丁

我在@patch使用单元测试时遇到了一些问题，修补了导入后，似乎没有拾取模拟，而是使用了“常规”类

我尝试测试的类和方法如下所示（为方便起见，将其简化）

from sila2lib.sila_server import SiLA2Server
# ... snip ...

class DeviceService:

def __init__(self, central_message_queue: asyncio.Queue, config: Config):

    self.central_message_queue: asyncio.Queue = central_message_queue
    self.logger = logging.getLogger('GWLogger')

    # ...... snip ......

async def start_device_server(self, tag_config: dict) -> asyncio.Queue:

    # Message queue used for passing messages to running device features (instrument readings)
    name = tag_config["Name"]
    uuid = tag_config["UUID"]
    cfg = tag_config["FeatureConfig"]

    # SiLA Server Setup [This is what I want to mock]
    self.device_server = SiLA2Server(name=name,
                                     description="Provides Device specific functions",
                                     server_uuid=uuid,
                                     port=self.device_server_port,
                                     ip=self.device_server_address,
                                     simulation_mode=False,
                                     key_file=None,
                                     cert_file=None)

    # ........ snip .......

还有一个示例测试-我要做的就是用替换掉SilaServer，MagicMock这样我就可以验证是否已使用正确的参数调用了方法

import asynctest, asyncio
from tests.util.MockConfig import build_mock_config
from unittest.mock import patch, MagicMock
from services.device.DeviceService import DeviceService

class DeviceServiceTests(asynctest.TestCase):

@patch("services.device.DeviceService.SiLA2Server")
async def test_device_info_load(self, mock_sila_server_class):

    mock_sila_server_instance = MagicMock()
    mock_sila_server_class.return_value = mock_sila_server_instance
    message_queue = asyncio.Queue()
    device_service = DeviceService(message_queue, build_mock_config())
    device_service.logger = MagicMock()

    await device_service.start_device_server(empty_tag_config)

    # Test feature has been set
    mock_sila_server_instance.add_feature.assert_called_with(data_path='',
                                                             feature_id='DeviceInfo',
                                                             servicer=None)

    # Check that server was started
    mock_sila_server_instance.run.assert_called_with(block=False)

和项目结构

由于未使用模拟程序，因此测试运行并失败，并且我得到了您所期望的断言异常，添加了一个断点并device_service使用实际类检查了

我觉得这确实很明显，但我看不到，我有其他类似的测试可以很好地与@patch装饰器配合使用，但是在这些测试中的应用方式似乎没有任何区别

任何帮助都非常感谢