I am working on a package in Python. I use virtualenv. I set the path to the root of the module in a .pth path in my virtualenv, so that I can import modules of the package while developing the code and do testing (Question 1: is it a good way to do?). This works fine (here is an example, this is the behavior I want):
(VEnvTestRc) zz@zz:~/Desktop/GitFolders/rc$ python
Python 2.7.12 (default, Jul 1 2016, 15:12:24)
[GCC 5.4.0 20160609] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> from rc import ns
>>> exit()
(VEnvTestRc) zz@zz:~/Desktop/GitFolders/rc$ python tests/test_ns.py
issued command: echo hello
command output: hello
However, if I try to use PyTest, I get some import error messages:
(VEnvTestRc) zz@zz:~/Desktop/GitFolders/rc$ pytest
=========================================== test session starts ============================================
platform linux2 -- Python 2.7.12, pytest-3.0.5, py-1.4.31, pluggy-0.4.0
rootdir: /home/zz/Desktop/GitFolders/rc, inifile:
collected 0 items / 1 errors
================================================== ERRORS ==================================================
________________________________ ERROR collecting tests/test_ns.py ________________________________
ImportError while importing test module '/home/zz/Desktop/GitFolders/rc/tests/test_ns.py'.
Hint: make sure your test modules/packages have valid Python names.
Traceback:
tests/test_ns.py:2: in <module>
from rc import ns
E ImportError: cannot import name ns
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! Interrupted: 1 errors during collection !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
========================================= 1 error in 0.09 seconds ==========================================
(VEnvTestRc) zz@zz:~/Desktop/GitFolders/rc$ which pytest
/home/zz/Desktop/VirtualEnvs/VEnvTestRc/bin/pytest
I am a bit puzzled, it looks like this indicates an import error, but Python does it fine so why is there a problem specifically with PyTest? Any suggestion to the reason / remedy (Question 2)? I googled and stack-overflowed the 'ImportError: cannot import' error for PyTest, but the hits I got were related to missing python path and remedy to this, which does not seem to be the problem here. Any suggestions?
Found the answer:
DO NOT put a __init__.py file in a folder containing TESTS if you plan on using pytest. I had one such file, deleting it solved the problem.
This was actually buried in the comments to the second answer of PATH issue with pytest 'ImportError: No module named YadaYadaYada' so I did not see it, hope it gets more visibility here.
I can't say I understand why this works, but I had the same problem and the tests work fine if I run python -m pytest.
I'm in a virtualenv, with pytest also available globally:
(proj)tom@neon ~/dev/proj$ type -a python
python is /home/tom/.virtualenvs/proj/bin/python
python is /usr/bin/python
(proj)tom@neon ~/dev/proj$ python -V
Python 3.5.2
(proj)tom@neon ~/dev/proj$ type -a pytest
pytest is /home/tom/.virtualenvs/proj/bin/pytest
pytest is /usr/bin/pytest
(proj)tom@neon ~/dev/proj$ pytest --version
This is pytest version 3.5.0, imported from /home/tom/.virtualenvs/proj/lib/python3.5/site-packages/pytest.py
I just solved this by removing the __init__.py in my project root:
.
├── __init__.py <--- removed
├── models
│ ├── __init__.py
│ ├── address.py
│ ├── appointment.py
│ └── client.py
├── requirements.txt
├── setup.cfg
├── tests
│ ├── __init__.py
│ ├── models
│ │ ├── __init__.py
│ │ ├── appointment_test.py
│ │ └── client_test.py
│ └── other_test.py
└── script.py
I had the same problem but for another reason than the ones mentioned:
I had py.test installed globally, while the packages were installed in a virtual environment.
The solution was to install pytest in the virtual environment. (In case your shell hashes executables, as Bash does, use hash -r, or use the full path to py.test)
This problem will happen if you have a tests.py file and a tests folder with tests/__init__.py.
During the collection pytest finds the folder, but when it tries to import the test files from the folder, tests.py file will cause the import problem.
To fix simply remove the tests.py file and put all your tests inside the tests/ folder.
For your specific case the fix will be precisely:
- Remove the file
/home/zz/Desktop/GitFolders/rc/tests.py - Make sure
/home/zz/Desktop/GitFolders/rc/tests/__init__.pyis present
I had a similar issue, exact same error, but different cause. I was running the test code just fine, but against an old version of the module. In the previous version of my code one class existed, while the other did not. After updating my code, I should have run the following to install it.
sudo pip install ./ --upgrade
Upon installing the updated module running pytest produced the correct results (because i was using the correct code base).
Install the packages into Your virtual environment.
Then start a new shell and source Your virtual environment again.
In my case, the import error occurred because the package is pointing to another package/directory with the same name and its path is one level above the folder I actually wanted. I think this also explains why some people need to remove _ init _.py while others need to add back.
I just put print(the_root_package.__path__) (after import the_root_package) in both python console and pytest scripts to compare the difference
BOTTOM LINE: When you do python, the package you import may be different from the package when you run pytest.
Another special case:
I had the problem using tox. So my program ran fine, but unittests via tox kept complaining. After installing packages (needed for the program) you need to additionally specify the packages used in the unittests in the tox.ini
[testenv]
deps =
package1
package2
...
The answer above not work for me. I just solved it by appending the absolute path of the module which not found to the sys.path at top of the test_xxx.py (your test module), like:
import sys
sys.path.append('path')
Had a similar issue and it worked when I added init.py file under tests directory.
I was getting this using VSCode. I have a conda environment. I don't think the VScode python extension could see the updates I was making.
python c:\Users\brig\.vscode\extensions\ms-python.python-2019.9.34911\pythonFiles\testing_tools\run_adapter.py discover pytest -- -s --cache-clear test
Test Discovery failed:
I had to run pip install ./ --upgrade
Edit your conftest.py and add following lines of code:
import os, sys
sys.path.insert(0, os.path.abspath(os.path.join(os.path.dirname(file), '..')))
And if trying to run the test case through terminal, use following ex:
python -m pytest test_some_step_file_steps.py --html=HTML_step_file_output.html --self-contained-html
It could be that Pytest is not reading the package as a Python module while Python is (likely due to path issues). Try changing the directory of the pytest script or adding the module explicitly to your PYTHONPATH.
Or it could be that you have two versions of Python installed on your machine. Check your Python source for pytest and for the python shell that you run. If they are different (i.e. Python 2 vs 3), use source activate to make sure that you are running the pytest installed for the same python that the module is installed in.
For anyone who tried everything and still getting error,I have a work around.
In the folder where pytest is installed,go to pytest-env folder.
Open pyvenv.cfg file.
In the file change include-system-site-packages from false to true.
home = /usr/bin
include-system-site-packages = true
version = 3.6.6
Hope it works .Don't forget to up vote.
If you already have .pyc files, try to delete them.
Today, I encounter this problem, here is what happend:
first I run pytest in mac (this will generate pyc files) then I launch a docker container (the os is alpine), with project dir mounted, and then when I try to run pytest in container, ImportError happens. after cleaning all pyc files, no error any more.
Hope this may be helpful.
If it is related to python code that was originally developed in python 2.7 and now migrated into python 3.x than the problem is probably related to an import issue.
e.g.
when importing an object from a file: base that is located in the same directory this will work in python 2.x:
from base import MyClass
in python 3.x you should replace with base full path or .base
not doing so will cause the above problem.
so try:
from .base import MyClass
if you need a init.py file in your folder make a copy of the folder and delete init.py in that one to run your tests it works for local projects. If you need to run test regularly see if you can move your init.py to a separate file.
[Resolved]
Before directly jumping into the solution of removing/ adding __init__.py, we might also want to look at how the imports are been done in your classes. Actually, I lost a day playing around with just __init__.py thinking that might be the problem :) However, that was quite informative.
In my case, it was the wrong way of calling classes from one python class to another python class which was throwing ImportError. Fixed the way classes/ modules to be called and it worked like charm. Hope, this helps others as well.
And yes, for similar error, we might have different solutions depending on how the code is written. Better to spend more time on self debugging. Lesson Learnt :) Happy coding!!!
来源：https://stackoverflow.com/questions/41748464/pytest-cannot-import-module-while-python-can