Error3 reports
Fix ModuleNotFoundError
in pytest
✅ Solution
The "ModuleNotFoundError" in pytest usually indicates that a required Python package or module isn't installed or isn't in the Python path being used by pytest. To fix this, ensure that all necessary packages are installed, ideally using `pip install <package_name>`, and verify that your PYTHONPATH environment variable or pytest configuration correctly points to the location of the missing module if it's a custom one. You may need to activate the correct virtual environment if the module is installed there.
Related Issues
Real GitHub issues where developers encountered this error:
pytest 9.0.3 + Python 3.14: "ValueError: I/O operation on closed file" in capture teardown when collection short-circuits inside a dot-prefix path (Windows)May 27, 2026
Allow dotted test filenames (`*.test.py`) via one-line change to `compute_module_name`May 24, 2026
Pytest tmpdir crashes on Python 3.13+/Windows when no username env vars are set (getpass.getuser now raises OSError)Oct 21, 2025
Timeline
First reported:Mar 6, 2025
Last reported:May 27, 2026