Question

我正在编写一个创建subprocess.Popen管道的程序。我正在尝试模拟subprocess.Popen，以便每个调用都返回一个不同的MagicMock，以便确保在管道中的特定（或所有）进程上调用方法。

我还希望基于subprocess.Popen对这个模拟进行自动指定，但是不断收到我无法基于模拟自动指定的错误。

当前我的代码如下：

@pytest.fixture
def Popen(mocker: 'pytest_mock.MockFixture'):
    def popen_factory(*args, **kwargs):
        popen = mocker.MagicMock()  # mocker.create_autospec(subprocess.Popen)
        popen.stdin = open(os.devnull, "wb")
        popen.stdout = open(os.devnull, "rb")
        popen.wait.return_value = 0
        return popen

    Popen = mocker.patch.object(subprocess, 'Popen', autospec=True)
    Popen.side_effect = popen_factory
    yield Popen

Answer 1

由于mocker.patch.object(subprocess, 'Popen', autospec=True)覆盖了subprocess.Popen，因此我必须将现有值分配给局部变量，并改用它。

@pytest.fixture
def Popen(mocker: 'pytest_mock.MockFixture'):
    real_Popen = subprocess.Popen

    def popen_factory(*args, **kwargs):
        popen = mocker.create_autospec(real_Popen)
        popen.stdin = open(os.devnull, "wb")
        popen.stdout = open(os.devnull, "rb")
        popen.wait.return_value = 0
        return popen

    Popen = mocker.patch.object(subprocess, 'Popen', autospec=True)
    Popen.side_effect = popen_factory
    yield Popen

每次实例化该类时，如何模拟Python类以返回唯一的autospec Mock实例？

1 个答案: