pytest-env

Install

Per https://stackoverflow.com/a/39162893/13697228:

conda install -c conda-forge pytest-env

Or:

pip install pytest-env

pytest.ini

Create pytest.ini file in project directory:

[pytest]
env = 
    ENV_VAR=RandomStuff

Python

In your code, load environment variables as you normally would:

import os
env_var = os.environ["ENV_VAR"]

pytest / VS Code

Either run:

pytest

(Notice how it says configfile: pytest.ini)

C:\Users\sterg\Documents\GitHub\sparks-baird\mp-time-split> pytest
==================================== test session starts ===================================== platform win32 -- Python 3.9.12, pytest-7.1.1, pluggy-1.0.0 rootdir:
C:\Users\sterg\Documents\GitHub\sparks-baird\mp-time-split,
configfile: pytest.ini plugins: anyio-3.6.1, cov-3.0.0, env-0.6.2
collecting ...

Or:

This only seems to work with breakpoints that have manually been set, I'm guessing some other change is needed to pause on errors.

Python for VS Code Extension

Apparently the Python for VS Code extension recognizes a .env file automatically. E.g. .env file:

ENV_VAR=RandomStuff

Haven't verified, but I'd assume this has the same behavior as using pytest-env with a pytest.ini file.

When all else fails

When I don't feel like dealing with the strange hackery necessary to get VS Code, Anaconda environments, and pytest playing nicely together (and/or forget how I fixed it before), I call my tests manually and run it like a normal script (see below). This may not work with more advanced pytest trickery using fixtures for example. At the end of your Python script, you can add something like:

if __name__ == "__main__":
    my_first_test()
    my_second_test()

and run it in debug mode (F5) as normal.

I suggest that you try like this:

• make sure that your VS Code workspace is set to the parent directory of (the root directory) PACKAGENAME
• add an empty __init__.py file in testsdirectory
• in test_main.py, replace from PACKAGENAME import * with from PACKAGENAME.main import *

To set up VS Code to use a specific pytest.ini file, you need to do the following:

1. Open a directory in VS Code (ctrl+k > ctrl+o)
2. Select a Python interpreter (ctrl+shift+p > Python: Select Interpreter > Python interpreter)
3. Configure the testing framework you want to use, in this case PyTest (ctrl+shift+p > Python: Configure Tests > Pytest > {pytest rootdir}
4. Open the settings.json file generated inside the .vscode/ directory that was created in your working directory (the one you chose in step 1)
5. Add the following setting to the file (it may already exist if you specified a rootdir when configuring pytest):

    "python.testing.pytestArgs": [
        "-c",
        "/path/to/your/pytest.ini"
    ],

That's it! VS Code should be using the pytest.ini file you specify in the last argument. You can specify any CLI options you want there.

Source

This may end up being a short term issue. Two workarounds fix it for me, as per comments in GitHub issue VS Code python unittest fails to import modules outside tests folder.

A. Revert the version of Python extension in VSCode from v2023.12.0 to v2023.8.0.

B. Insert setting "python.experiments.optOutFrom": ["pythonTestAdapter"] into the User Settings (not the Workspace Settings). Be mindful of trailing commas.

I can now debug python unittest tests.

Update

The bug that led to this issue was fixed in Python extension v2023.19.

After much experimentation I finally found how to do it. What I needed was to pass user name and password to my script in order to allow the code to log into a test server. My test looked like this:
my_module_test.py

import pytest
import my_module

def login_test(username, password):
    instance = my_module.Login(username, password)
    # ...more...

conftest.py

import pytest

def pytest_addoption(parser):
    parser.addoption('--username', action='store', help='Repository user')
    parser.addoption('--password', action='store', help='Repository password')

def pytest_generate_tests(metafunc):
    username = metafunc.config.option.username
    if 'username' in metafunc.fixturenames and username is not None:
        metafunc.parametrize('username', [username])

    password = metafunc.config.option.password
    if 'password' in metafunc.fixturenames and password is not None:
        metafunc.parametrize('password', [password])

Then in my settings file I can use:
.vscode/settings.json

{
    // ...more...
    "python.testing.autoTestDiscoverOnSaveEnabled": true,
    "python.testing.unittestEnabled": false,
    "python.testing.nosetestsEnabled": false,
    "python.testing.pytestEnabled": true,
    "python.testing.pytestArgs": [
        "--exitfirst",
        "--verbose",
        "test/",
        "--username=myname",
        "--password=secret",
    // ...more...
    ],
}

An alternative way is to use pytest.ini file instead:
pytest.ini

[pytest]
junit_family=legacy
addopts = --username=myname --password=secret