python module_error ai_generated true

ModuleNotFoundError: No module named 'myapp'

ID: python/pytest-import-mode-src-not-found

Also available as: JSON · Markdown · 中文
80%Fix Rate
87%Confidence
0Evidence
2024-05-21First Seen

Version Compatibility

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

Root Cause

pytest's default import mode (prepend) inserts test directories into sys.path, not the project root. A src/ layout package isn't importable from tests without installation or path configuration.

generic

中文

pytest 默认 import 模式（prepend）将测试目录插入 sys.path，而非项目根目录。src/ 布局的包在未安装或未配置路径时无法从 tests 导入。

Workarounds

  1. 95% success 
    pip install -e .
# or with pyproject.toml [build-system] set, uv pip install -e .
  2. 90% success 
    # pyproject.toml
[tool.pytest.ini_options]
pythonpath = ["src"]
addopts = "--import-mode=importlib"

Dead Ends

Common approaches that don't work:

  1. 70% fail

    Relative paths break depending on CWD; also pollutes sys.path and hides packaging issues.

  2. 60% fail

    Works locally but isn't reproducible in CI; pytest may still use prepend mode and shadow the path.