Question

我有一个简单的模块：

# my_module
from os.path import join
from os import environ

some_file_name = 'foo.txt'

def file_path():
    join(environ['TARGET_DIRECTORY'], some_file_name)

一个简单的测试：

import os
import unittest
from os.path import join

from mock import patch
from my_module import some_file_name, file_path


class MyTest(unittest.TestCase):
    def test_can_create_path(self):
        some_folder = '/path/to/directory'
        with patch.dict('my_module.environ', {'TARGET_DIRECTORY': some_folder}):
            self.assertEqual(file_path(), join(some_folder, some_file_name))

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

我预计对environ['TARGET_DIRECTORY']的调用会返回'/path/to/directory'，但会返回None

Answer 1

您的函数会返回None，因为没有明确的return语句。添加return：

def file_path():
    return join(environ['TARGET_DIRECTORY'], some_file_name)

模拟补丁工作正常。

Python mock，patch os.environ返回None

1 个答案: