python / python/typeshed

mock.patch.object type annotation fails with **kwargs

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stubs: false positive
Dominant language
Python
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Description

https://mypy-play.net/?mypy=latest&python=3.10&gist=6f7d6d1036646b8e8a41ed3a5dab3b98&flags=strict

from unittest import mock
import subprocess


def foo() -> None:
    with mock.patch.object(
        subprocess,
        "Popen",
        **{"return_value.communicate.side_effect": KeyboardInterrupt}
    ):
        pass

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  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start by running the linked mypy playground example with strict checking and confirm the failure around mock.patch.object and the **kwargs argument. Then inspect the unittest.mock stubs in typeshed; done means the example type-checks correctly and the behavior is covered by a regression test.

Written by the indexing model from the issue text.

Assessment

Tech stack
python
Domain
testing-qa
Issue type
Bug
Difficulty
3/5
Estimated time
1-2 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
35/100

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