How to integrate VSCode with pytest ('test discovery fails')?

Question

I'm unable to integrate my project's unit tests into VSCode. Test discovery fails because source files are not recognized by pytest.

(Just for clarification, this is a question about VSCode, not about pytest. I'm here because VSCode links its question section to SOF. Tests work fine if I run them manually.)

Tooling: pyenv, pipenv, pytest.

Project layout:

/src -> source code
/tests/unit -> test code

.vscode/settings.json:

{
    "python.envFile": "${workspaceFolder}/.env",
    "python.testing.pytestEnabled": true,
    "python.testing.pytestArgs": [
        "tests"
    ],
    "python.testing.unittestEnabled": false,
    "python.testing.nosetestsEnabled": false
    [...]
}

.env:

PYTHONPATH=./src

(Note: I don't think .env matters here, as per this comment, under Use of the PYTHONPATH variable)

Test discovery fails with:

tests/unit/test_revoke_default_sg.py:7: in <module>
    from revokedefaultsg.app import RevokeDefaultSg, UnknownEventException
E   ModuleNotFoundError: No module named 'revokedefaultsg'
=========================== short test summary info ============================
ERROR tests/unit/test_revoke_default_sg.py
!!!!!!!!!!!!!!!!!!!! Interrupted: 1 error during collection !!!!!!!!!!!!!!!!!!!!
=============================== 1 error in 0.08s ===============================

This is caused by ./src not being part of the python path, so tests cannot import source code.

I can fix this on CLI/makefile level by adding to PYTHONPATH:

PYTHONPATH=./src pytest

This works as expected.

What's the correct setup for VSCode?

Am I supposed to create a launch configuration for testing? I've started to look into this, but couldn't get it to work nicely with pipenv.

Several issues coming together here, pytest itself should have a [configuration file](https://docs.pytest.org/en/latest/customize.html#config-file-formats) with `pytest.ini` being the simplest option. Then, there's configuration of the `src` layout, `setup.py` with `package_dir` is [the simplest option](https://stackoverflow.com/questions/14417236). From your description it's a good question if you [activated your venv](https://stackoverflow.com/questions/62498127). Your PYTHONPATH will be relative to OS and/or venv depending how you separated things. Should be mostly independent of the IDE... — bad_coder, Aug 12 '20 at 22:44
I'm a PyCharm user, I don't know if VSCode comes with testing functionalities builtin. What I just said are the steps to get the tools working on a console/shell independently of IDE integration features. For the IDE I use the standard integration tools that provide a GUI for a part of what I just described (but most of it has to be configured by hand all the same). — bad_coder, Aug 12 '20 at 22:50
it's been awhile since I've done this, and my layout is different, but what I ended up doing on at least one project is in the .vscode/settings.json file: 1. set the python.pythonPath and 2. set python.testing.pytestEnabled: true (I have other test frameworks disabled). Then, run via `pipenv run python -m pytest src` — Hikash, Aug 12 '20 at 22:56
This seems very specific to [JSON](https://stackoverflow.com/tags/json/info) and [PYTHONPATH](https://stackoverflow.com/tags/pythonpath/info) you may consider adding those tags. — bad_coder, Aug 12 '20 at 23:22
I have been using pytest with Visual Code for quite some time. What I usually do is that I put the tests within the src. I would try that first to see if there is something else wrong with the configuration. Then I would try and fiddle around with the user json. — NMech, Aug 13 '20 at 04:42

Jan Groth · Accepted Answer · 2020-08-13T20:44:25.973

(OP here)

I think the key to integrate into VSCode creating a specific launch configuration for pytest (before, I only had the default launch configuration that's been created with the Python extension).

I now have two configurations (.vscode/launch.json):

{
    "version": "0.2.0",
    "configurations": [
        {
            "name": "Python: Run Current File",
            "type": "python",
            "request": "launch",
            "program": "${file}",
            "console": "integratedTerminal",
            "env": {
                "PYTHONPATH": "./src"
            }
        },
        {
            "name": "Python: pytest",
            "type": "python",
            "request": "launch",
            "module": "pytest",
            "cwd": "${workspaceRoot}",
            "env": {
                "PYTHONPATH": "./src"
            },
            "envFile": "${workspaceRoot}/.env",
            "console": "integratedTerminal",
        }
    ]
}

(project on GitHub)

Running this configuration after launching VSCode discovers tests correctly, without raising errors. However, I have not tried it out in different projects yet.

Also, maybe I didn't find the right section of the VSCode documentation, but this feels heavily under-documented. I ended up searching GitHub for gists with launch configs and copied together whatever seemed vaguely helpful...

Brilliant answer! This is the only way I found I could discover all tests and debug them for flasgger... — Louis Go, Nov 09 '21 at 07:57

How to integrate VSCode with pytest ('test discovery fails')?

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