In python, mocking an object using
@patch('foo.bar')
def test_things(self, bar):
bar.return_value= ...
requires that all tested classes use
import foo
and can not use
from foo import bar
In the second case code under test uses the original object, as mock patches names rather than the function itself. This feels very brittle.
How do we write mocks which will work with both forms of import?
Short answer: No
The principle of a mock is to mock one object. If you import the same object from different ways in you your code (which is somehow weird) you need to create a mock for each object.
Example:
import os
from os.path import isdir
from unittest.mock import patch
>>> with patch('os.path') as mock_os_path:
... mock_os_path.isdir.return_value = "Hello"
... mocked_res = os.path.isdir("./")
... res = path.isdir("./")
... print("mocked_res)
... print(res)
...
Hello
True
According to docs
target should be a string in the form 'package.module.ClassName'. The target is imported and the specified object replaced with the new object, so the target must be importable from the environment you are calling patch() from. The target is imported when the decorated function is executed, not at decoration time.
