Wrapping pytest call with default test path

[Novakov]

Project I'm working on is using wrapper around pytest that automatically generates few required custom parameters and we recently found issue with explicit file paths. As I was not able to narrow down the problem to simple & small use case, repository https://github.com/Novakov/pytest-path-problem contains detailed description and reproduction of the issue.

It can be summarised with: how can I tell pytest to use directory X if no other directory/file is provided (so call pytest --base-dir=X is equal to pytest X and pytest --base-dir=X file1.py is equal to pytest file1.py).

It is quite possible that it is not possible to do (and I'm okay with that) but I'm not giving up hope yet, any suggestion what I can try is welcome.

[portyu9]

Hi @Novakov

The wrapper should not always append hw_tests as a positional argument.

pytest already has the behavior you want through testpaths: it supplies default test paths when no explicit test target is given, while an explicit file/directory on the command line takes precedence.

Put the default in pytest configuration, for example:

[pytest]
testpaths = hw_tests

and make the wrapper invoke pytest without adding hw_tests itself:

cmdline = [
    sys.executable,
    "-m",
    "pytest",
    "--argument",
    "abc",
    *sys.argv[1:],
]

Because your wrapper should work from arbitrary directories, also run pytest with the project/config directory as its working directory:

subprocess.run(cmdline, cwd=project_root)

Then:

do_test

uses testpaths, while:

do_test hw_tests/test_hw_1.py

uses only that explicitly supplied test file, so it is not collected once through the directory and a second time through the file.

This also gives pytest a consistent place from which to discover the root configuration/conftest containing --argument.

Please mark this answer as accepted if it helped, thank you.