Python importing a module from a parallel directory

How would I organize my python imports so that I can have a directory like this.

project
|      \
|      __init__.py
|     
src
|   \
|    __init__.py
|    classes.py
|
test
    \
     __init__.py
     tests.py

And then inside /project/test/tests.py be able to import classes.py

I've got code looking like this in tests.py

from .. src.classes import(
    scheduler
    db
)

And am getting errors of

SystemError: Parent module '' not loaded, cannot perform relative import

Anyone know what to do?

Solution

Python adds the folder containing the script you launch to the PYTHONPATH, so if you run

python test/tests.py

Only the folder test is added to the path (not the base dir that you're executing the command in).

Instead run your tests like so:

python -m test.tests

This will add the base dir to the python path, and then classes will be accessible via a non-relative import:

from src.classes import etc

If you really want to use the relative import style, then your 3 dirs need to be added to a package directory

package
* __init__.py
* project
* src
* test

And you execute it from above the package dir with

python -m package.test.tests