Structuring your project guide leads to a ModuleNotFoundError in the tests module

[isaiahstjohn]

Following this section, adding from .context import sample in my tests module gives me the following error: ModuleNotFoundError: No module named '__main__.context'; '__main__' is not a package

I was able to fix it by removing the . from from .context import sample, but I suspect that's not the ideal solution. I know that the from .context import sample is a relative import statement as described in PEP 328, but I just do not understand modules, packages, absolute and relative imports, etc. enough to say what's going on here.

I tried creating ./__init__.py and ./tests/__init__.py files, but that did not help.

Finally, I tried the following:

~> git clone git@github.com:navdeep-G/samplemod.git
~> python3 samplemod/tests/test_basic.py
Traceback (most recent call last):
  File "samplemod/tests/test_basic.py", line 3, in <module>
    from .context import sample
ModuleNotFoundError: No module named '__main__.context'; '__main__' is not a package

I'm not alone in hitting this issue. @rileyweber13 originally reported this problem a year ago.

[AghastComet]

Relative imports only work in a package that is being imported due to using the __name__ variable that is set to "__main__" if the file is ran directly. If you import test_basic.py, it should work to run test_basic.sample. If you take out the period, you lose the ability to import the tests from elsewhere so what you want depends on how you're using the tests.

[nuno-andre]

Python tests are usually coded to be executed through a testing framework. In this case

cd <yourproject>
python -m pytest tests
# either:
# py.test tests