--cov as final element in addopts creates confusing behaviour

[ego-thales]

Hi there,

I'm not sure this is a pytest bug but here it goes.

I have the following pyproject.toml configuration

[tool.pytest.ini_options]
testpaths = "test"
addopts = [
    "--import-mode=importlib",  # Recommended by pytest
    "--cov",
]

so I can easily use

pytest

to start my tests.

Now when I want to test only a specific file, doing

pytest specific/file.py

ignores the argument, while in the mean time, passing another optional argument such as the following

pytest -s specific/file.py

works perfectly as intended.

Am I missing a piece or is this a pytest-side problem?

Thanks in advance!

All the best.
Élie

[RonnyPfannschmidt]

I believe a argument to the cov option is missing

[RonnyPfannschmidt]

Indeed the cov option expects a argument

Provide that or remove it from addopts

[eliegoudout]

Thanks for your answer.

I think then it might be a problem of pytest-cov since they recommend not giving it when using source configuration:

If you have multiple sources it might be easier to set those in .coveragerc and always use --cov (without a value) instead of having a long command line with --cov=pkg1 --cov=pkg2 --cov=pkg3 ....

Do you +1 or am I missing something else? If appropriate, I will maybe ask for help or open an issue directly at pytest-cov.

[RonnyPfannschmidt]

I believe the examples put options instead of filename after it so it works

This definitely needs better docs

[RonnyPfannschmidt]

I checked the docs they use the --cov=somename variant

We probably need a warning

[eliegoudout]

I think a warning could be a first step indeed.

Also, I think my case can easily be solved simply by swapping the order of my options in my config file so that --cov is already followed by another option? I cannot test this week-end.

Finally, maybe they could use a special character to mean "use from source" (e.g. --cov=!).
It could even be automatically added if configuration file ends with --cov, but this may not be a desirable behaviour.

[RonnyPfannschmidt]

• determine if we can add a warning
• document the error

[ionelmc]

Would using "--cov=" (just that) achieve the desired result? It would not eat up following arguments.

[ionelmc]

If not maybe we could implement a special value, eg: --cov=* or --cov=?