python type_error ai_generated true

TypeError: _mock_children() got an unexpected keyword argument 'autospec' File ".../unittest/mock.py", line ..., in __init__ self._mock_children = {}

ID: python/unittest-mock-autospec-call-arg

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80%Fix Rate
81%Confidence
0Evidence
2024-05-28First Seen

Version Compatibility

VersionStatusIntroducedDeprecatedNotes
3.x active — — —

Root Cause

A custom Mock subclass overrides __init__ without forwarding **kwargs to super().__init__, so attributes like autospec/spec_set are silently dropped or cause errors when combined with `create_autospec`.

generic

中文

自定义 Mock 子类覆盖了 __init__ 但未将 **kwargs 转发给 super().__init__，导致 autospec/spec_set 等属性被静默丢弃，或在配合 `create_autospec` 时引发错误。

Workarounds

  1. 95% success 
    from unittest.mock import Mock

class MyMock(Mock):
    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)
  2. 92% success 
    from unittest.mock import create_autospec

mock_client = create_autospec(MyClient, instance=True)
mock_client.fetch.return_value = {"ok": True}

Dead Ends

Common approaches that don't work:

  1. 75% fail

    Loses signature checking; tests pass with typos in method names, defeating the purpose.

  2. 80% fail

    The subclass __init__ swallows the kwarg, so autospec is not applied.