Pytest import error despite using conftest in root directory?

Question

I have the following directory structure:

src 
    \conftest.py
    \dir_A
        \run_A.py
        \test_run_A.py
    \dir_B
        \run_B.py

where run_A.py has the following code:

from dir_B import run_B

...

When I run pytest from src , I get the error:

ImportError while importing test module '/home/user/src/dir_A/run_A.py'
...

ImportError: cannot import name 'run_B'

Is there a reason why this fails despite using conftest.py?

I'd like to add that running python3 -m dir_A.test_run_A from src works perfectly fine as a test.

Answer 1

You'll find this link helpful: https://docs.pytest.org/en/latest/pythonpath.html

Essentially, when running these tests from the src directory, pytest will walk all the way down to /home/user/src/dir_A/run_A.py . Without any __init__.py files, it will then refuse to walk anywhere else, as it doesn't realize it is part of a larger package.