Inconsistent behaviour of `python3 -m pytest` and `py.test`

[sils]

See http://pastebin.com/52ra33eN

Both commands show

platform linux -- Python 3.4.3 -- py-1.4.30 -- pytest-2.7.2
rootdir: /home/lasse/prog/PyPrint, inifile: setup.cfg
plugins: spec, cov, xdist

but py.test isn't able to get the imports right.

Steps to reproduce:

• git clone https://github.com/coala-analyzer/PyPrint
• git checkout pytestrep (Auto sync with origin/pytestrep)
• py.test/python3 -m pytest in a python3 environment

[sils]

The error is that I missed to put __init__.py files in the package. Still I find this inconsistent behaviour alarming, there's probably a bug behind that. Also note that I got similarly weird results when running python -m pytest on CI: it worked only for python 3.3 and 3.4 but not for 3.2 and pypy 3.2 which raised the import error agian.

[RonnyPfannschmidt]

@sils1297 this is a artifact of the new style namespaces

[Zearin]

Perhaps you should raise a Warning to let the user know this may occur. (Bonus points for adding a notice to the documentation, too...but the immediate relevancy of a Warning in the terminal is a better first step, IMO.)

[ssangervasi]

I am also seeing different behavior between py.test and python -m pytest using Python 2.7. The latter always works, while the former can only find tests if I have __init__.py in my test directories. Technically init files solve the issue, but this is explicitly advised against in the pytest documentation.

@RonnyPfannschmidt is there any further reading on "new style namespaces"?

[RonnyPfannschmidt]

@ssangervasi new style namespaces where introduced in python3 - there no longer is a __init__.py with a namespace declaration needed

can you perhaps show full output of the invocation

another potential issue in your case is pythonpath vs imports in tests vs rootdirs which is unrelated to this issue

[ssangervasi]

@RonnyPfannschmidt thanks for the reply. You were correct and I now understand that my issue was unrelated. I was overlooking the fact that python -m ... adds the current directory to PYTHONPATH.

[RonnyPfannschmidt]

Py.test never does that unless there is a toplevel conftest, please give US more information

[santagada]

Seeing the same problem, python3 -m pytest works and py.test doesn't for xonsh. it is a PYTHONPATH issue and the docs are very misleading in http://docs.pytest.org/en/latest/usage.html#cmdline:

python -m pytest [...]
This is equivalent to invoking the command line script py.test [...] directly.

no they are not, exactly because of pythonpath. Can we just do that on py.test?

[DuncanBetts]

Perhaps you should raise a Warning to let the user know this may occur. (Bonus points for adding a notice to the documentation, too...but the immediate relevancy of a Warning in the terminal is a better first step, IMO.)

Perhaps Pull 2085 implementing @enkore's suggestion here adds this?

[nicoddemus]

@DuncanBetts I'm not sure I follow, it seems the error is not really related to --pyargs, but the fact that python -m pytest implicitly adds the current directory to PYTHONPATH.

Either way I think updating the documentation would be a good first step as well.

[nicoddemus]

This should be documented in https://docs.pytest.org/en/latest/pythonpath.html