Python path modification when using pytest directly

[pmeier]

Imagine I have a conda env like this

1. conda create -n pytest-q python=3.8
2. conda activate pytest-q
3. pip install pytest

If I look at the Python path now, it looks like this:

$ python -c 'import sys; print("\n".join(sys.path))'
/home/philip/.conda/envs/pytest-q/lib/python38.zip
/home/philip/.conda/envs/pytest-q/lib/python3.8
/home/philip/.conda/envs/pytest-q/lib/python3.8/lib-dynload
/home/philip/.conda/envs/pytest-q/lib/python3.8/site-packages

Imagine further, I have a test.py module like this:

import sys


def test():
    print("\n".join(sys.path))

Running pytest through Python gives this result

$ echo $PWD
/home/philip/git/nebari-dev/nebari
$ python -m pytest -sq test.py
/home/philip/git/nebari-dev/nebari
/home/philip/.conda/envs/pytest-q/lib/python38.zip
/home/philip/.conda/envs/pytest-q/lib/python3.8
/home/philip/.conda/envs/pytest-q/lib/python3.8/lib-dynload
/home/philip/.conda/envs/pytest-q/lib/python3.8/site-packages
.
1 passed in 0.00s

As explained here, it is standard Python behavior to include the current working directory. Meaning everything is good here.

However, running pytest directly yields

$ pytest -sq test.py
/home/philip/git/nebari-dev/nebari
/home/philip/.conda/envs/pytest-q/bin
/home/philip/.conda/envs/pytest-q/lib/python38.zip
/home/philip/.conda/envs/pytest-q/lib/python3.8
/home/philip/.conda/envs/pytest-q/lib/python3.8/lib-dynload
/home/philip/.conda/envs/pytest-q/lib/python3.8/site-packages

So not only was the current working directory added as well, the binary directory of my conda env, i.e. $CONDA_PREFIX/bin, was added as well.

Is this expected? I couldn't find any documentation on this.

Edit:

Ok, this has nothing to do with conda. Can reproduce the same behavior inside a virtualenv.

[RonnyPfannschmidt]

that seems like a bug, whats the operating system and where is the python from

[RonnyPfannschmidt]

So the key question is how the paths come to be for those setups

So these happen to non conda python interpreters

[pmeier]

Yes, this does seem to happen on non-conda Python binaries as well.

$ nix-shell -p python38Packages.pytest
$ python -VV
Python 3.8.16 (default, Dec  6 2022, 19:12:06) 
[GCC 11.3.0]
$ pytest -V
pytest 7.1.3
$ python -m pytest -sq test.py | head -n3
/home/philip
/nix/store/25zarrb1q1wpin34vh20am0hlfzkv0rc-python3.8-pytest-7.1.3/lib/python3.8/site-packages
/nix/store/0jcddjpn4wnx6pyr6hlmxw3xzgszqm81-python3.8-attrs-22.1.0/lib/python3.8/site-packages
$ pytest -sq test.py | head -n3
/home/philip
/nix/store/25zarrb1q1wpin34vh20am0hlfzkv0rc-python3.8-pytest-7.1.3/bin
/nix/store/25zarrb1q1wpin34vh20am0hlfzkv0rc-python3.8-pytest-7.1.3/lib/python3.8/site-packages

[pmeier]

Want me to open a proper issue for this?

[RonnyPfannschmidt]

Does it happen on non-nix pythons, nix has numerous hacks in place that may play a role

[pmeier]

The last option that I have available is an Arch box. It seems the behavior is the same:

❯ python -VV
Python 3.10.10 (main, Mar  5 2023, 22:26:53) [GCC 12.2.1 20230201]
❯ pytest -V
pytest 7.3.0
❯ python -m pytest -sq test.py | head -n3
/home/philip
/usr/lib/python310.zip
/usr/lib/python3.10
❯ pytest -sq test.py | head -n3
/home/philip
/usr/bin
/usr/lib/python310.zip

[nicoddemus]

I get similar results on Windows:

(cwd is c:\Users\bruno\projects\pytest)

λ python -m pytest -sq .tmp\test_p.py
c:\Users\bruno\projects\pytest\.tmp
c:\Users\bruno\projects\pytest
C:\Users\bruno\AppData\Local\Programs\Python\Python310\python310.zip
...

λ pytest -sq .tmp\test_p.py
c:\Users\bruno\projects\pytest\.tmp
C:\Users\bruno\projects\pytest\.env310\Scripts\pytest.exe
C:\Users\bruno\AppData\Local\Programs\Python\Python310\python310.zip
...

(Note C:\Users\bruno\projects\pytest\.env310\Scripts\pytest.exe being in sys.path in the second call)

So I don't think this is architecture/OS specific.

[pmeier]

This is also not an issue from the pytest "binary" that is autogenerated:

❯ cat $(which pytest)
#!/home/philip/.conda/envs/nebari-dev/bin/python3.8
# -*- coding: utf-8 -*-
import re
import sys
from pytest import console_main
if __name__ == '__main__':
    sys.argv[0] = re.sub(r'(-script\.pyw|\.exe)?$', '', sys.argv[0])
    sys.exit(console_main())

pytest/src/pytest/__main__.py

Lines 1 to 5 in 61f7c27

	"""The pytest entry point."""
	import pytest
	if __name__ == "__main__":
	raise SystemExit(pytest.console_main())