使用 mock 测试目录是否存在 [英] Using mock to test if directory exists or not

问题描述

这几天我一直在探索 mock 和 pytest.

I have been exploring mock and pytest for a few days now.

我有以下方法:

def func():
    if not os.path.isdir('/tmp/folder'):
        os.makedirs('/tmp/folder')

为了进行单元测试，我决定打补丁os.path.isdir和os.makedirs，如图:

In order to unit test it, I have decided to patch os.path.isdir and os.makedirs, as shown:

@patch('os.path.isdir')
@patch('os.makedirs')
def test_func(patch_makedirs, patch_isdir):
    patch_isdir.return_value = False
    assert patch_makedirs.called == True

断言失败，与 patch_isdir 的返回值无关.有人可以帮我弄清楚我哪里出错了吗?

The assertion fails, irrespective of the return value from patch_isdir. Can someone please help me figure out where I am going wrong?

推荐答案

不能肯定有完整的代码，但我感觉它与 你打补丁的地方.

Can't say for sure having the complete code, but I have the feeling it's related to where you're patching.

您应该修补由被测模块导入的 os 模块.

You should patch the os module that was imported by the module under test.

所以，如果你有这样的:

So, if you have it like this:

mymodule.py:

def func():
    if not os.path.isdir('/tmp/folder'):
        os.makedirs('/tmp/folder')

你应该像这样制作你的_test_mymodule.py_:

you should make your _test_mymodule.py_ like this:

@patch('mymodule.os')
def test_func(self, os_mock):
    os_mock.path.isdir.return_value = False
    assert os_mock.makedirs.called

请注意，这个特定的测试并没有那么有用，因为它本质上是在测试模块 os 是否有效——您可以假设它已经过良好的测试.;)

Note that this specific test is not that useful, since it's essentially testing if the module os works -- and you can probably assume that is well tested. ;)

如果专注于您的应用程序逻辑(也许是调用 func 的代码?)，您的测试可能会更好.

Your tests would probably be better if focused on your application logic (maybe, the code that calls func?).

这篇关于使用 mock 测试目录是否存在的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！