为什么我不能为我的单元测试从不同的文件中修补 class？

Question

我有一个名为 some.py 的文件：

from dataclasses import dataclass
from some_folder.some_reader import SomeReader

class SomeClass:
    def __init__(self, url):
        self.reader = SomeReader(url)

和some_reader.py:

class SomeReader:
    def read_path(self, url):
        return "read_path"

和some_test.py:

from unittest.mock importpatch
from some_folder.some import SomeClass

@patch("some_folder.some_reader.SomeReader")
def test_some_class(mock_some_reader):
    SomeClass("")

当我运行some_test时，似乎实例化的SomeReader不是模拟对象，而是：

SomeReader
<class 'some_folder.some_reader.SomeReader'>

如果我把 SomeReader 放在 some.py 中似乎一切正常。

Answer 1

见Where to patch

some.py:

from some_folder.some_reader import SomeReader


class SomeClass:
    def __init__(self, url):
        self.reader = SomeReader(url)

some_folder/some_reader.py:

class SomeReader:
    def read_path(self, url):
        return "read_path"

test_some.py:

import unittest
from unittest.mock import patch
from some import SomeClass


class TestSome(unittest.TestCase):
    @patch("some.SomeReader")
    def test_some_class(self, mock_some_reader):
        some = SomeClass("")
        print(some.reader)

if __name__ == '__main__':
    unittest.main()

测试结果：

<MagicMock name='SomeReader()' id='4520784368'>
.
----------------------------------------------------------------------
Ran 1 test in 0.001s

OK

为什么我不能为我的单元测试从不同的文件中修补 class？

Why can't I patch a class from a different file for my unit test?

python

unit-testing

mocking

python-unittest

python-mock