"py.test" vs "pytest" command

Question

The

py.test

command is failing in my case, whereas

pytest

is running totally fine.

I use the pytest-flask plugin:

platform linux -- Python 3.5.2, pytest-3.0.2, py-1.4.31, pluggy-0.3.1

rootdir: /home/sebastian/develop/py/flask-rest-template, inifile: 

plugins: flask-0.10.0

When I invoke

$ py.test

I get the following error:

Traceback (most recent call last):

  File "/usr/local/lib/python3.5/dist-packages/_pytest/config.py", line 301, in _getconftestmodules

    return self._path2confmods[path]

KeyError: local('/home/sebastian/develop/py/flask-rest-template')



During handling of the above exception, another exception occurred:

Traceback (most recent call last):

  File "/usr/local/lib/python3.5/dist-packages/_pytest/config.py", line 332, in _importconftest

    return self._conftestpath2mod[conftestpath]

KeyError: local('/home/sebastian/develop/py/flask-rest-template/conftest.py')



During handling of the above exception, another exception occurred:

Traceback (most recent call last):

  File "/usr/local/lib/python3.5/dist-packages/_pytest/config.py", line 338, in _importconftest

    mod = conftestpath.pyimport()

  File "/usr/local/lib/python3.5/dist-packages/py/_path/local.py", line 650, in pyimport

    __import__(modname)

  File "/usr/local/lib/python3.5/dist-packages/_pytest/assertion/rewrite.py", line 207, in load_module

    py.builtin.exec_(co, mod.__dict__)

  File "/home/sebastian/develop/py/flask-rest-template/conftest.py", line 2, in <module>

    from app.app import create_app

  File "/home/sebastian/develop/py/flask-rest-template/app/app.py", line 1, in <module>

    from flask import Flask

ImportError: No module named 'flask'

ERROR: could not load /home/sebastian/develop/py/flask-rest-template/conftest.py

This is my actual

conftest.py

file:

import pytest

from app.app import create_app



@pytest.fixture

def app():

    app = create_app()

    return app

My project structure is as like:

.

├── app

│   ├── __init__.py

│   ├── app.py

│   └── config.py   # flask configuration objects

├── conftest.py     # pytest configruation

├── requirements.txt

├── ...

└── tests

    └── ...

So, what is the difference between the two commands? And why is one failing and the other not?

update 1

1) I had to change my relative imports

from .config import Config

or

from config import Config

to absolute ones like

from app.config import Config

2) Running flask with

python3 -m app.app

3) now

pytest

and

py.test

work normal

Thank you very much for your help, folks!

update 2

This is getting weird... when using absolute imports, running python with the

-m

option and flask with

debug=True

then the

werkzeug

library is not reloading the sources as expected:

http://chase-seibert.github.io/blog/2015/06/12/flask-werkzeug-reloader-python-dash-m.html

https://github.com/pallets/werkzeug/issues/461

https://github.com/pallets/flask/issues/1246

This helped me in my

app/app.py

:

if __name__ == '__main__':

    app.run(debug=True, use_reloader=False)

Then

python -m app.app

works fine.

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Answer 1

To answer the question about the actual command (meaning the invocation of the tool on the command line) in a bit more detail:

The py.test invocation is the old and busted joint. pytest is the new hotness (since 3.0). py.test and pytest invocations will coexist for a long time I guess, but at some point py.test might be deprecated. So I would recommend to #dropthedot.

[...] so from pytest 3.0 we will supported and recommend use of pytest as the main command instead of py.test. It's possible that in future we will deprecate py.test and potentially even remove it.

-- Dave Hunt

Backwards compatibility is a very important concern for the pytest community, so the old way might never go away and it's not much of a maintenance burden to keep it anyway (it is just defined as a different entry point in setup.py).

"py.test" vs "pytest" command

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