How to configure VS code for pytest with environment variable - visual-studio-code

Question

I am trying to debug pytest. I would like to inject an environment variable. Here is how I have set launch.json
{
"type": "python",
"request": "test",
"name": "pytest",
"console": "integratedTerminal",
"env": {
"ENV_VAR":"RandomStuff"
}
},
But it seems when I start debugging. I do not see the env variable injected, as a result my test which expects that env variable fails.
Also I notice error
Could not load unit test config from launch.json

Answer 1

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.

Answer 2

Could not really figure out how to fix "unit" test debugging with Vscode. But with Pytest one can call tests like python -m pytest <test file>(https://docs.pytest.org/en/stable/usage.html#cmdline)
That means Vscode can be configured like a module
"configurations": [
{
"name": "Python: Module",
"type": "python",
"request": "launch",
"module": "pytest",
"args": ["--headful","--capture=no", "--html=report.html"],
}
This is good enough to do debugging of python tests. Also you can then insert environment variables
"env": {
"ENV_VAR":"RandomStuff"
}

Answer 3

This works in v 1.72.2
Create in the workspace folder:
.vscode/launch.json
Similar to the OP, but using "module"
{
"version": "0.2.0",
"configurations": [
{
"name": "Pytest",
"type": "python",
"request": "launch",
"module": "pytest",
"console": "integratedTerminal",
"env": {
"testy": "someval"
}
}
]
}
Try some breakpoints (either in test files or app code)
Start the debugger
Watch the os.environ['testy'] value (must import os where the breakpoint is of course)