我正在處理以下問題，我有一個類，我想模擬其補丁的異步方法：class ExampleClass: async def asy_method(self, param): return await some_coroutine(self, param)example_instance = ExampleClass()我只想打補丁await example_instance.asy_method('test_param')通常我會用mocker.patch('ExampleClass.asy_method', new_callable=AsyncMock)其中，mocker是pytest-mock插件的固定裝置，而AsyncMock具有以下形式class AsyncMock(mock.MagicMock): async def __call__(self, *args, **kwargs): return super(AsyncMock, self).__call__(*args, **kwargs)這會給我一個Mock對象，它在調(diào)用時的行為像協(xié)程。問題是，我想訪問self傳遞給方法的屬性。self僅在您進行設置的情況下才傳遞給模擬對象 autospec=True（另請參閱Python Doc，了解如何修補未綁定的方法），您不能與一起使用new_callable。有誰知道如何解決這個問題？
1 回答
眼眸繁星
TA貢獻1873條經(jīng)驗 獲得超9個贊
確實，您不能混合使用自動指定和新的可調(diào)用項。相反，可以自動指定方法，然后替換side_effect屬性，并為其指定一個AsyncMock()實例：
from unittest import mock
def configure_coroutine_mock(mock_function, klass=AsyncMock):
"""Make an autospecced async function return a coroutine mock"""
mock_function.side_effect = AsyncMock()
# mark the side effect as a child of the original mock object
# so transitive access is recorded on the parent mock too. This is
# what .return_value does normally
mock._check_and_set_parent(
mock_function.mock, mock_function.side_effect,
None, '()')
return mock_asy_method.side_effect
with mocker.patch('ExampleClass.asy_method', autospec=True) as mock_asy_method:
configure_coroutine_mock(mock_asy_method)
因為AsyncMock()是可調(diào)用的對象，所以每次mock_asy_method調(diào)用都會調(diào)用，并將參數(shù)傳遞給該對象。然后，該調(diào)用的結果用于從返回mock_asy_method()：
>>> from unittest import mock
>>> class ExampleClass:
... async def asy_method(self, param):
... return await some_coroutine(self, param)
...
>>> example_instance = ExampleClass()
>>> with mock.patch('__main__.ExampleClass.asy_method', autospec=True) as mock_asy_method:
... configure_coroutine_mock(mock_asy_method)
... print(example_instance.asy_method('foo')) # call to patched class coroutine
... print(mock_asy_method.mock_calls) # calls are recorded
...
<AsyncMock name='asy_method()' id='4563887496'>
<coroutine object AsyncMock.__call__ at 0x1100780f8>
[call(<__main__.ExampleClass object at 0x10ffac1d0>, 'foo')]
如您所見，self參數(shù)和參數(shù)記錄在調(diào)用中，因為這mock_asy_method是一種適當?shù)暮瘮?shù)。
當然，只有在AsyncMock()實際等待返回的呼叫結果時，我們才會看到該呼叫也被記錄：
>>> with mock.patch('__main__.ExampleClass.asy_method', autospec=True) as mock_asy_method:
... configure_coroutine_mock(mock_asy_method)
... loop = asyncio.get_event_loop()
... coro = example_instance.asy_method('foo')
... loop.run_until_complete(coro)
... print(mock_asy_method.mock_calls)
...
<AsyncMock name='asy_method()' id='4564408920'>
<AsyncMock name='asy_method()()' id='4564999360'>
[call(<__main__.ExampleClass object at 0x10ffac1d0>, 'foo'),
call()(<__main__.ExampleClass object at 0x10ffac1d0>, 'foo')]
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