python config_error ai_generated true

E pytest.PytestAssertRewriteWarning: Module already imported so cannot be rewritten

ID: python/pytest-assertion-introspection-error

Also available as: JSON · Markdown · 中文
80%Fix Rate
82%Confidence
0Evidence
2024-12-12First Seen

Version Compatibility

VersionStatusIntroducedDeprecatedNotes
7.x active — — —
8.x active — — —

Root Cause

A plugin or conftest imports a module before pytest's assertion rewriter can register it, so assert statements in that module are not rewritten and produce poor failure messages.

generic

中文

插件或 conftest 在 pytest 断言重写器注册之前导入了模块，导致该模块中的 assert 语句未被重写，产生较差的失败信息。

Workarounds

  1. 90% success 
    Register the module for rewriting before any import:

# conftest.py (top)
import pytest
pytest.register_assert_rewrite('myapp.core')

import myapp.core  # after registration
  2. 85% success 
    Avoid importing application modules at conftest top level; import inside fixtures instead.

Dead Ends

Common approaches that don't work:

  1. 85% fail

    The warning is suppressed but assertion rewriting remains disabled for that module.

  2. 80% fail

    Import order still places it after pytest's plugin loading in many cases, so the warning persists.