Python Unittest: No tests discovered in Visual Studio Code

Question

I'm trying to make the self-running feature of Visual Studio Code unit tests work. I recently made a change in the directory structure of my Python project that was previously like this:

myproje\
    domain\
        __init__.py
    repositories\
    tests\
        __init__.py
        guardstest.py
    utils\
        __init__.py
        guards.py
    web\

And my setup for unittest was like this:

    "python.unitTest.unittestArgs": [
    "-v",
    "-s",
    "tests",
    "-p",
    "*test*.py"
]

After the changes, the structure of the project was as follows:

myprojet\
    app\
        controllers\
            __init__.py
        models\
            __init__.py
            entities.py
            enums.py
        tests\
            res\
                image1.png
                image2.png
            __init__.py
            guardstest.py
        utils\
            __init__.py
            guards.py
        views\
            static\
            templnates\
        __init__.py         
    uml\

After that the extension does not discover my tests anymore. I've tried to change the '-s' parameter to "./app/tests", ".tests", "./tests", "app/tests", "/app/tests", "app.tests", unsuccessfully .

Answer 1

The problem was that I was using relative imports in the test module (from ..utils import guards). I just changed it to absolute import (from app.utils import guards) and it all worked again.

Answer 2

It is because some of the imports in the test is not discoverable. when running python -m unittest -h, the last line of the output is

For test discovery all test modules must be importable from the top level directory of the project.

it is likely that VSCode is running the command without the right PYTHONPATH and other environment variables.

I created __init__.py and put the following code into it.

import sys
import os
import unittest

# set module path for testing
sys.path.insert(0, "path_in_PYTHONPATH")
# repead to include all paths

class TestBase(unittest.TestCase):
    def __init__(self, methodName: str) -> None:
        super().__init__(methodName=methodName)

then in the test file, instead of extending unittest.TestCase, do

from test import TestBase 

class Test_A(TestBase):
    ...