Python unittest import problems

Question

I'm having a tough time understanding packages, and specifically how to use unittest with packages. I looked at this question () but the correct answer to that question didn't solve my problem. I have the following structure:

model
|-- __init__.py
|-- boardmodel.py
|
|-- exceptions
|   |
|   |-- __init__.py
|   |-- exceptions.py
|
|-- test
    |-- __init__.py
    |-- test_boardmodel.py

With the following files/imports:

model/__init__.py:

import model.exceptions.exceptions
import model.boardmodel

model/exceptions/__init__.py:

contains nothing

model/test/__init__.py:

contains nothing

imports inside boardmodel.py::

from model.exceptions.exceptions import ZeroError, OverlapError, ArgumentError, ProximityError

imports inside test_boardmodel.py:

import unittest

from model.boardmodel import Board, Ball, Wall
from model.exceptions.exceptions import ProximityError

I place myself in the model-directory and I run python -m unittest test.test_boardmodel.py. I get the following message:

ERROR: test_boardmodel (unittest.loader._FailedTest)
----------------------------------------------------------------------
ImportError: Failed to import test module: test_boardmodel
Traceback (most recent call last):
  File "/usr/local/Cellar/python3/3.6.2/Frameworks/Python.framework/Versions/3.6/lib/python3.6/unittest/loader.py", line 153, in loadTestsFromName
    module = __import__(module_name)
  File "/Users/sahandzarrinkoub/Documents/Programming/pythonfun/BouncingBalls/balls/src/model/test/test_boardmodel.py", line 3, in <module>
    from model.boardmodel import Board, Ball, Wall
ModuleNotFoundError: No module named 'model'

I'm a bit lost with how the imports work and what location the modules/packages are looked for when an import statement is executed. Why isn't model found?

I shall add that if I remove model. from all the imports listed, the tests work, but I can't use the package from "outside" anymore:

src
|-- visual.py
|
|-- model
    |-- __init__.py
    |-- boardmodel.py
    |
    |-- exceptions
    |   |
    |   |-- __init__.py
    |   |-- exceptions.py
    |
    |-- test
        |-- __init__.py
        |-- test_boardmodel.py

inside visual.py:

import model
from model.boardmodel import Board

Answer 1

I was facing the same issue, being able to import some modules from several files, but not from a test file, so I saw this solution:

If you have test/my_test.py, tests should be run as:

python -m test.my_test

After that, I imported what I wanted and got no errors.