ModuleNotFoundError with pytest
PythonPython 3.xDockerPytestPython Problem Overview
I want my tests folder separate to my application code. My project structure is like so
myproject/
myproject/
myproject.py
moduleone.py
tests/
myproject_test.py
myproject.py
from moduleone import ModuleOne
class MyProject(object)
....
myproject_test.py
from myproject.myproject import MyProject
import pytest
...
I use myproject.myproject
since I use the command
python -m pytest
from the project root directory ./myproject/
However, then the imports within those modules fail with
> E ModuleNotFoundError: No module named 'moduleone'
I am running Python 3.7 and have read that since 3.3, empty __init__
files are no longer needed which means my project becomes an implicit namespace package
However, I have tried adding an __init__.py
file in myproject/myproject/
and also tried adding a conftest.py
file in myproject/
but neither works
I have read answers that say to mess with the paths and then upvoted comments in other questions saying not to.
What is the correct way and what am I missing?
EDIT;
Possibly related, I used a requirements.txt
to install pytest using pip. Could this be related? And if so, what is the correct way to install pytest in this case?
EDIT 2:
One of the paths in sys.path
is /usr/src/app/
which is a docker volume lined to /my/local/path/myproject/
.
Should the volume be /my/local/path/myproject/myproject/
instead?
Python Solutions
Solution 1 - Python
Not sure if this solution was specific to my problem, but I simply add __init__.py
to my tests
folder and that solved the problem.
Solution 2 - Python
PYTHONPATH
env. var
Solution: use the PYTHONPATH=. pytest
As mentioned by @J_H, you need to explicitly add the root directory of your project, since pytest
only adds to sys.path
directories where test files are (which is why @Mak2006's answer worked.)
Good practice: use a Makefile or some other automation tool
If you do not want to type that long command all the time, one option is to create a Makefile
in your project's root dir with, e.g., the following:
.PHONY: test
test:
PYTHONPATH=. pytest
Which allows you to simply run:
make test
Another common alternative is to use some standard testing tool, such as tox.
Solution 3 - Python
Be sure to include .
dot in the $PYTHONPATH
env var.
Use $ python -m site
, or this code fragment to debug such issues:
import pprint
import sys
pprint.pprint(sys.path)
Your question managed to use myproject
at three different levels. At least during debugging you might want to use three distinct names, to reduce possible confusion.
Solution 4 - Python
In my case I added a __init__.py
to my test directory with this inside it:
import sys
sys.path.append('.')
My app code is at the same level as my test directory.
Solution 5 - Python
Kept everything same and just added a blank test file at the root folder .. Solved
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.
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 <module>
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 ==============================
Solution 6 - Python
In my case it is because I installed pytest
on the system level but not in my virtual environment.
You can test this by python -m pytest
. If you see ModuleNotFoundError: No module named 'pytest'
then your pytest
is at the system level.
Install pytest
when the virtual environment is activated will fix this.
Solution 7 - Python
So it seems that the sys.path
has to include the application directory rather than the project root folder containing the application directory and test directory.
So in my case /my/local/path/myproject/myproject/
had to be in sys.path
rather than /my/local/path/myproject/
.
Then I could run pytest
in /my/local/path/myproject/
(didn't need python -m pytest
). This meant that the modules within /myproject/myproject/
could find each other and the tests as well without any namespace nesting.
So my tests looked like
from moduleone import ModuleOne
import pytest
def test_fun():
assert ModuleOne.example_func() == True
That said, there seem to be many gotchas, so I have no idea if this is correct..
Solution 8 - Python
Using poetry and pytest 5.4.3, I had the following structure (some folders / files have been removed for clarity):
project structure
.
├── my_app
│ ├── __init__.py
│ ├── main.py
│ ├── model.py
│ └── orm.py
├── poetry.lock
├── pyproject.toml
├── README.rst
└── tests
├── __init__.py
├── conftest.py
├── test_my_app.py
└── utilities
└── db_postgresql_inmemory.py
tests/conftest.py
pytest_plugins = [
"utilities.db_postgresql_inmemory",
]
which generated a module not found error for the fixture:
ImportError: Error importing plugin "utilities.db_postgresql_inmemory": No module named 'utilities'
None of the other answers have worked for me, as I have tried to add:
[me@linux ~/code/my_app]touch tests/utilities/__init__.py
[me@linux ~/code/my_app]touch ./test_blank.py
I could make the import from conftest.py work by REMOVING both __init__.py
files:
[me@linux ~/code/my_app]rm tests/utilities/__init__.py tests/__init__.py
Solution 9 - Python
I suggest you have a code structure like this:
myproject/
helpers/
moduleone.py
moduletwo.py
tests/
myproject_test.py
conftest.py
And the content of conftest.py file is:
pytest_plugins = ['helpers']
Run pytest
again.
Solution 10 - Python
I ran into this issue as well and am using poetry for dependency management and direnv for my project specific environment variables. Please note, I am relatively new to Python so I don't know if this is the correct fix.
Here is my entire .envrc file:
layout_poetry() {
if [[ ! -f pyproject.toml ]]; then
log_error 'No pyproject.toml found. Use `poetry new` or `poetry init` to create one first.'
exit 2
fi
local VENV=$(poetry env list --full-path | cut -d' ' -f1)
if [[ -z $VENV || ! -d $VENV/bin ]]; then
log_error 'No created poetry virtual environment found. Use `poetry install` to create one first.'
exit 2
fi
VENV=$VENV/bin
export VIRTUAL_ENV=$(echo "$VENV" | rev | cut -d'/' -f2- | rev)
export POETRY_ACTIVE=1
PATH_add "$VENV"
}
layout poetry
export PYTHONDONTWRITEBYTECODE=1
export PYTHONPATH="$PWD/project_name"
I don't know if I need to layout poetry because it is supposed to be creating virtual environments for us already but this is what I coworker recommended so I went with it. Layout poetry also didn't work without that function and it didn't like when I added it to my zshenv so I added it here.
For this specific question, the last line is the money maker.
Solution 11 - Python
ANOTHER SUGGESTION
See this answer: https://stackoverflow.com/a/69691436/595305
Solution 12 - Python
I was facing the issue which i resolved by
- Installing
pytest
at the root of my project usingpip install pytest
- Adding blank
__init__.py
in the sibling of mytest_file.py
which i wanted to execute.
Solution 13 - Python
In my case, I've created a separate app for testing with both __init__.py
and conftest.py
at the same level. After deleting __init__.py
error was gone.
Credit goes to qci-amos
Solution 14 - Python
I have resolved it by adding export PYTHONPATH="your root dir/src"
i.e.
export PYTHONPATH="/builds/project/src"
poetry run pytest .....
Solution 15 - Python
The simplest solution I found was to manually add my target module to syspath. Lets say you have a structure like this:
flaskapp
- src
-- app.py
-- utils
-- ...
- tests
docs
venv
This makes my test
folder a sibling to my module's src
folder. If I start putting test_*
files that need to import some of the module's code, I can simply:
import src.utils.calculator
And this would be fine until I try to import a file that imports another file from the module. The solution is simple: add a __init__.py
to your tests
folder, and put this line inside:
import sys, os
sys.path.insert(0, os.path.abspath(os.path.join(os.path.dirname(__file__), '../src')))
And just modify the last part relative to your module location and folder name
Solution 16 - Python
For me, when I was checking my project structure I found parent directory and sub directory having same names. When I changed the directory name, I got it working. So,
# Did not work
- same_name_project/
- same_name_project/
- tests/
# Worked
- different_named_project/
- a_unique_directory/
- tests/