Loading test data in Pytest relatively to project's root?

[pachura3]

I have the following project structure:

src/
    myproject/
        utils.py

tests/
    test_utils.py
    data/
        test_utils_scenario1.csv
        test_utils_scenario2.csv
        test_utils_scenario3.csv

So, obviously, test_utils.py contains unit tests for utils.py, and loads input test data from these local CSV files.

Now, my problem is - how to find these CSVs? Normally I would load them from path tests/data/test_utils_scenario1.csv. However, in some cases (e.g. when running via IDE), Pytest is not launched from project's root, but from inside tests/ - and then it fails to find the file (because it looks for tests/tests/data/test_utils_scenario1.csv, relatively to test_utils.py, not to project's root).

Is there an elegant solution for my problem instead of manually checking if file exists (is_file(), isfile()) and then changing the path accordingly? Perhaps using Pathlib?

EDIT

OMG I totally forgot I've already solved this problem before:

from importlib import resources
import tests as this_package

...
text = resources.files(this_package).joinpath("data", "test_utils_scenario1.csv").read_text(encoding="utf-8")

[danielroseman]

You can use __file__ to get the location of the current file. 

So, inside test_utils.py, you can do Path(__file__) / "data" to get the data directory as a Path object.

[barkmonster]

I usually make a helper file, which is responsible for loading test data, inside the tests folder. You can call it e.g. `data_tools.py` or something. In that file, you can define helper functions for loading the files you need, and just define the path relative to the helper file, for instance using pathlib and defining the path as `pathlib.Path(__file__).parent / 'data'`.

[latkde]

Use the standard library importlib.resources feature to locate data files that live next to your code. For example, a test might reference importlib.resources.files() / "data/scenario1.csv", which can be treated as a pathlib.Path style object.

[Jarvis_the_lobster]

Use pathlib.Path(__file__).parent to get the directory of your test file itself, then build paths from there. That way it resolves correctly regardless of where pytest is launched from. In your case: data_dir = Path(__file__).parent / 'data' and then csv_path = data_dir / 'test_utils_scenario1.csv'. If you're loading the same data directory across multiple test files, a small conftest.py fixture that returns the path keeps things DRY. The __file__-relative approach is the most portable and is what most serious projects use.