Python imports for tests using nose - what is best practice for imports of modules above current package
Solution 1
You have answered your question pretty well already.. D (install to system location) is preferred for distributable code. I usually use C (modify sys.path) because I don't want system-wide installs of my hundreds of custom libs. In theory A (relative import) seems nicer, but there are cases where it fails. B (PYTHONPATH) is right out, really only for testing purposes in my opinion.
That pretty much sums up all of the options. The option you prefer (Python magically knows where to look) is really not a workable solution because it can lead to unpredictable results, such as automagically finding libraries from unrelated projects.
In my opinion, the best thing to do is put this at the entry point(s) to your program:
import sys, os
sys.path = [os.path.abspath(os.path.dirname(__file__))] + sys.path
Solution 2
I had the same problem and found an answer in a related question work for me.
Just remove the __init__.py in the project root.
Solution 3
I know there is a answer checked and I still think it's a good reason to share other alternatives :)
There is a nose-pathmunge giving you a control to set sys.path
while invoking nosestests
.
leonigmig
Updated on July 08, 2022Comments
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leonigmig almost 2 years
This is a question which is asked frequently in different forms, and often obtains "lol you're not doing it properly" responses. Pretty sure that's because there's a common sense scenario people (including me) are trying to use as an implementation, and the solution is not obvious (if you've not done it before).
Would accept an answer which "lets the fly out of the bottle".
Given
project/ __init__.py /code __init__.py sut.py /tests __init__.py test_sut.py
Where tests_sut.py starts:
import code.sut
Running nosetests in the root dir leads to:
ImportError: No module named code.sut
Avenues traveled:
a) do a relative using
from ..code import sut
b) add root of project to PYTHONPATH
c) use the
sys.path.append
to add the .. path before the imports at the start of each test module.
d) just remember to do a
setup.py
on the project to install the modules into the site-packages before running tests.
So the requirement is to have tests located beneath the test package root which have access to the project. Each of the above don't feel "natural" to me, have proved problematic or seem like too much hard work!
In java this works, but basically by dint of your build tool / IDE placing all your classes on the classpath. Perhaps the issue is I'm expecting "magic" from Python? Have noted in the Flask webframework tests, option d) seems to be preferred.
In any case, statements below recommending a preferred solution would remove the feeling of "unnaturalness" in my own.
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leonigmig almost 13 yearsbut i guess my entry point(s!) is the nosetests command! i considered going down the route of writing a nosetests wrapper calling nose.run after sys.path append.. but again it felt unnatural. thanks for this, it will help me press on.
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Luke almost 13 yearsIf you are running through nosetests, then the entry points are the individual modules that are imported, and this will be very awkward. In this case, you might find PYTHONPATH to be the least awkward option (as I said, it's ok for testing purposes). I feel your pain here--I'm also hoping more people chime in to make it seem ok (or to suggest a better solution).
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frabcus over 10 yearsGreat answer! I had an old __init__.pyc left over causing me this problem.
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user541905 about 9 yearsThis did not help me, how is this supposed to work out?
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furins about 9 years@user541905: because nose intelligently try to populate your
sys.path
. A good explanation from django-nose itself: github.com/django-nose/… -
neurotempest almost 9 yearsSurprisingly this did work for me - Although I feel that nose should actually add the current working directory to
sys.path
(just as the python unitest module does) as well as the directory containing the top of the current package tree -
Zeinab Abbasimazar almost 6 yearsI think it's better to use
append
instead of+
.