問題描述

我嘗試使用 mock 在 python 中編寫一些單元測試.

I try to use mock to write some unit-tests in python.

例如我有以下課程:

class TCPHandler(socketserver.BaseRequestHandler):
    def handle(self):
        self.data = self.request.recv(1024).strip()

我只想測試 handle 方法.無需對 socketserver.BaseRequestHandler 做任何假設.例如，我想斷言 handle 使用參數 1024 調用 recv.可以用模擬做這樣的事情嗎?IE.用模擬替換基類 socketserver.BaseRequestHandler?還是我偏離了這個想法?

And I only want to test the handle method. Without having to assume anything about socketserver.BaseRequestHandler. I for example want to assert that handle calls recv with the argument 1024. Is it possible to do such thing with mock? I.e. replacing the base class socketserver.BaseRequestHandler with a mock? Or am I off track with that idea?

在 ecatmur 的回答下(謝謝！)我首先嘗試了以下方法:

With the answer of ecatmur (thank you!) I first tried the following:

patcher = patch.object(TCPHandler, '__bases__', (Mock,))
with patcher:
    patcher.is_local = True
    handler = TCPHandler()
    handler.handle()

但是現在 handle 不再被調用并且 dir(handler) 給出:

But now handle is not called anylonger and dir(handler) gives:

['assert_any_call', 'assert_called_once_with', 'assert_called_with', 'assert_has_calls', 'attach_mock', 'call_args', 'call_args_list', 'call_count', 'called', 'configure_mock', 'method_calls', 'mock_add_spec', 'mock_calls', 'reset_mock', 'return_value', 'side_effect']

type(handler) 給出<class 'mock.TCPHandler'>

我解釋說，修補基類也會將我的派生類變成一個模擬類.

Which I interpret that patching the base class also turns my derived class into a mock.

我現在嘗試了另一個想法:

I now gave another idea a try:

mock = MagicMock()
TCPHandler.handle(mock)
#assertions

但是模擬似乎沒有被調用.

However the mock seems not to be called.

推薦答案

您可以通過修補派生類的 __bases__ 來做到這一點:

You can do this by patching the derived class's __bases__:

def test_derived():
    patcher = mock.patch.object(Derived, '__bases__', (mock.Mock,))
    with patcher:
        patcher.is_local = True
        d = Derived()
        print d.foo()

is_local hack 是阻止 mock.patch 在反轉補丁時嘗試調用 delattr 所必需的.

The is_local hack is necessary to stop mock.patch from trying to call delattr when reversing the patch.

這篇關于如何使用 python 模擬庫模擬基類的文章就介紹到這了，希望我們推薦的答案對大家有所幫助，也希望大家多多支持html5模板網！