python module_error ai_generated true

ModuleNotFoundError: No module named 'mock'

ID: python/unittest-mock-not-found

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80%Fix Rate
89%Confidence
0Evidence
2024-01-17First Seen

Version Compatibility

VersionStatusIntroducedDeprecatedNotes
3.8 active — — —
3.12 active — — —

Root Cause

Code imports the standalone backport `mock` package, but it is not installed (or the project targets Python 3 where unittest.mock should be used). The backport was only needed for Python 2 or very old Python 3.

generic

中文

代码导入了独立的 `mock` 后端包，但未安装（或项目面向 Python 3，应使用 unittest.mock）。该后端包仅在 Python 2 或很旧的 Python 3 中才需要。

Workarounds

  1. 97% success 
    Replace the import with the stdlib module:

# from mock import patch  (remove)
from unittest.mock import patch, MagicMock

On Python 3.3+ this requires no installation.
  2. 90% success 
    If legacy code must keep `import mock`, install the backport: `pip install mock` and add it to requirements-dev.txt.

Dead Ends

Common approaches that don't work:

  1. 85% fail

    The test then runs without any mocking, so the real network or DB is hit and tests fail or hang for a different reason.

  2. 80% fail

    Old mock versions are incompatible with modern patch targets and pytest, causing AttributeError or patching failures.