[Pytest-commit] Issue #742: Difference of sys.path between running py.test and testdir.runpytest (pytest-dev/pytest)

[Daniel Hahler]

New issue 742: Difference of sys.path between running py.test and testdir.runpytest
https://bitbucket.org/pytest-dev/pytest/issue/742/difference-of-syspath-between-running

Daniel Hahler:

I've noticed that pytest's runpytest method fails when pies2overrides is
installed in the virtualenv, which adds a reprlib.py file into site-packages.

While this is clearly an [issue with
pies](https://github.com/timothycrosley/pies/issues/44), pytest is
triggering it by calling its script from this site-packages dir.

    % virtualenv venv
    % venv/bin/pip install pytest pies2overrides==2.6.5

    # Simulate `testdir.runpytest`:
    % venv/bin/python venv/lib/python3.4/site-packages/pytest.py

Maybe pytest could use another approach here to call itself?
And/or something like `sys.path.pop(0)` in the script?

I might be missing something here, of course, but it seems like the behaviour/setup of the Python path differs between running `py.test` and `runpytest`, which should be avoided.

Output:

    % virtualenv venv
    Using base prefix '/home/daniel/.pyenv/versions/3.4.3'
    New python executable in venv/bin/python3.4
    Also creating executable in venv/bin/python
    Installing setuptools, pip...done.

    % venv/bin/pip install pytest pies2overrides==2.6.5
    Collecting pytest
      Using cached pytest-2.7.0.tar.gz
    Collecting pies2overrides==2.6.5
      Using cached pies2overrides-2.6.5-py2.py3-none-any.whl
    Collecting py>=1.4.25 (from pytest)
      Using cached py-1.4.27-py2.py3-none-any.whl
    Collecting ipaddress (from pies2overrides==2.6.5)
      Using cached ipaddress-1.0.7.tar.gz
    Installing collected packages: py, pytest, ipaddress, pies2overrides
      Running setup.py install for pytest
      Running setup.py install for ipaddress
    Successfully installed ipaddress-1.0.7 pies2overrides-2.6.5 py-1.4.27 pytest-2.7.0

    % venv/bin/python venv/lib/python3.4/site-packages/pytest.py
    Traceback (most recent call last):
      File "venv/lib/python3.4/site-packages/pytest.py", line 9, in <module>
        import pytest
      File "/tmp/t/venv/lib/python3.4/site-packages/pytest.py", line 14, in <module>
        from _pytest.config import main, UsageError, _preloadplugins, cmdline
      File "/tmp/t/venv/lib/python3.4/site-packages/_pytest/config.py", line 2, in <module>
        import argparse
      File "/home/daniel/.pyenv/versions/3.4.3/lib/python3.4/argparse.py", line 86, in <module>
        import collections as _collections
      File "/tmp/t/venv/lib/python3.4/collections/__init__.py", line 17, in <module>
        from reprlib import recursive_repr as _recursive_repr
      File "/tmp/t/venv/lib/python3.4/site-packages/reprlib.py", line 3, in <module>
        from repr import *
    ImportError: No module named 'repr'
    shell returned 1