pytest cannot import module while python can

Question

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   gt  gt  gt  from rc import ns  gt  gt  gt  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  lt module gt      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

User · Answer

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.

User · Answer

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

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I was experiencing this issue today and solved it by calling python -m pytest from the root of my project directory    Calling pytest from the same location still caused issues   My Project dir is organized as   api   - server    - tests        - test routes py   - routes        - routes py  - app py   The module routes was imported in my test routes py as  from server routes routes import Routes  Hope that helps

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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   py is present

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I had placed all my tests in a tests folder and was getting the same error  I solved this by adding an init py in that folder like so     -- Pipfile  -- Pipfile lock  -- README md  -- api  -- app py  -- config py  -- migrations  -- pull request template md  -- settings py  -- tests      --   init   py  lt ------      -- conftest py      -- test sample py

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Had a similar issue and it worked when I added   init   py file under tests directory

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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

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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   39 ImportError  No module named YadaYadaYada  39  so I did not see it  hope it gets more visibility here

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Simply put an empty conftest py file in the project root directory  because when pytest discovers a conftest py  it modifies sys path so it can import stuff from the conftest module  A general directory structure can be  Root  -- conftest py  -- module1       --   init   py       -- sample py  -- tests      -- test sample py

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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

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I disagree with the posts saying that you must remove any   init   py files  What you must instead do is alter the sys path   Run an experiment where you print sys path when running the code normally  Then print sys path while running the code via pytest  I think you will find that there is a difference between these two paths  hence why pytest breaks   To fix this  insert the path from the first experiment at the 0th index of the second    Let   usr exampleUser Documents foo  be the first element of print sys path  for experiment 1    Below is code that should fix your issue   import sys sys path 0      usr exampleUser Documents foo    Put this at the top of your file  before your actual import statement   Source  I was dealing with this myself and the above process solved it

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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

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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

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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

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Yet another massive win for Python s import system  I think the reason there is no consensus is that what works probably depends on your environment and the tools you are using on top of it    I m using this from VS Code  in the test explorer under Windows in a conda environment  Python 3 8   The setup I have got to work is   mypkg        init   py     app py     view py tests      test app py     test view py   Under this setup intellisense works and so does test discovery   Note that I originally tried the following  as recommended here   src      mypkg            init   py         app py         view py tests      test app py     test view py   I could find no way of getting this to work from VS Code because the src folder just blew the mind of the import system  I can imagine there is a way of getting this to work from the command line  As a relatively new convert to Python programming it gives me a nostalgic feeling of working with COM  but being slightly less fun

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Install the packages into Your virtual environment  Then start a new shell and source Your virtual environment again

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In my case I am working in a container and unfortuantely pytest has the tendency to use python2 7 rather than my python3 interpreter of choice  In my case this worked  python3 -m pytest  My folder structure   app  -module1 py -module2 py -tests  --test module1 py --test module2 py requirements txt README md

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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

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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

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I had a similar problem just recently  The way it worked for me it was realizing that  quot setup py quot  was wrong Previously I deleted my previous src folder  and added a new one with other name  but I didn t change anything on the setup py  newbie mistake I guess   So pointing setup py to the right packages folder did the trick for me from setuptools import find packages  setup  setup      name  quot - gt  YOUR SERVICE NAME  lt - quot       extras Require dict test   quot pytest quot         packages find packages where  quot - gt CORRECT FOLDER lt - quot        package dir   quot  quot    quot - gt CORRECT FOLDER lt - quot       Also  not init py in test folder nor in the root one  Hope it helps someone    Best

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Kept everything same and just added a blank test file at the root folder    Solved it  Here are the findings  this problem really bugged me for a while   My folder structure was   mathapp      - server py       - configuration py      -   init   py      - static          - home html   tests                  - functional         - test errors py      - unit          - test add py   and pytest would complain with the ModuleNotFoundError and gives the HINT - make sure your test modules packages have valid Python names   I introduced a mock test file at the same level as mathsapp and tests directory  The file contained nothing  Now pytest does not complain    Result without the file     pytest                               test session starts                               platform win32 -- Python 3 8 2  pytest-5 4 2  py-1 8 1  pluggy-0 13 1 rootdir  C  mak2006 workspace 0github python-rest-app-cont collected 1 item   1 error                                      ERRORS                                                      ERROR collecting tests functional test func py                  ImportError while importing test module  C  mainak workspace 0github python-rest-app-cont tests functional test func py   Hint  make sure your test modules packages have valid Python names  Traceback  tests functional test func py 4  in  lt module gt      from mathapp service import sum E   ModuleNotFoundError  No module named  mathapp                              short test summary info                             ERROR tests functional test func py                     Interrupted  1 error during collection                                                     1 error in 0 24s                                   Results with the file     pytest                               test session starts                               platform win32 -- Python 3 8 2  pytest-5 4 2  py-1 8 1  pluggy-0 13 1 rootdir  C  mak2006 workspace 0github python-rest-app-cont collected 2 items  tests functional test func py                                              50   tests unit test unit py                                                   100                                   2 passed in 0 11s

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I just solved this by removing the   init   py in my project root      --   init   py  lt --- 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

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My 2 cents on this  pytest will fail at chance if you are not using virtual environments  Sometimes it will just work  sometimes not   Therefore  the solution is    remove pytest with pip uninstall create your venv activate your venv pip install your project path in editable mode  so it will be treated by pytest as a module  otherwise  pytest wont find your internal imports   You will need a setup py file for that install your packages  including pytest finally  run your tests   The code  using windows PowerShell   pip uninstall pytest python exe -m venv my env   my env Scripts activate  my env  pip install -e    my env  pip install pytest pytest-html pandas numpy   Then finally   my env  pytest --html  my testing report html    An example of setup py  for pip install -e   import setuptools  setuptools setup      name  my package       version  devel       author  erickfis       author email  erickfis gmail com       description  My package       long description  My gooood package       packages setuptools find packages        classifiers            Programming Language    Python    3            Operating System    OS Independent              include package data True

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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

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I solved my problem by setting the PYTHONPATH in Environment Variables for the specific configuration I m running my tests with  While you re viewing the test file on PyCharm   Ctrl   Shift   A Type Edit Configurations Set your PYTHONPATH under Environment  gt  Environment variables

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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

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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

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If you run Pytest from a terminal  Run pytest with the --import-mode append command-line flag  Argument description in the official documentation  https   docs pytest org en stable pythonpath html  UPD  Before I also wrote how to do the same if you use PyCharm  but community does not like extendend answers  so I removed additional information that probably was helpful to someone who have a similar issue

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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

[python] pytest cannot import module while python can

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