Change pytest working directory to test case directory

Question

I have the following pytest directory structure:

system_tests/
  ├── conftest
  ├── pytest.ini
  │
  ├── suite_1/
  │    └── test_A.py
  │   
  └── suite_2/
       └── sub_suite_2a/
            └── test_B.py

When each test method runs, a number of third-party libraries/processes generate artifacts in the current working directory.

• When pytest is executed from the sub_suite folder (using CLI or IDE "play" button), the files are generated in the sub_suite folder, where I want them to be.
• However, when pytest is run from the system_tests folder to run all tests, all artifacts are created in the system_tests folder, which is not what I want.

Is there an easy way to force pytest to always use the test class folder as the working directory so I get the same results regardless of how or where I run a test from?

Answer 1

The following function-level fixture will change to the test case directory, run the test (yield), then change back to the calling directory to avoid side-effects, as suggested by @hi2meuk:

@pytest.fixture
def change_test_dir(request):
    os.chdir(request.fspath.dirname)
    yield
    os.chdir(request.config.invocation_dir)

• request is a built-in pytest fixture
• fspath is the LocalPath to the test module being executed
• dirname is the directory of the test module
• request.config.invocationdir - the folder from which pytest was executed
• request.config.rootdir - pytest root, doesn't change based on where you run pytest. Not used here, but could be useful.

Any processes that are kicked off by the test will use the test case folder as their working directory and copy their logs, outputs, etc. there, regardless of where the test suite was executed.

EDIT: Improved Solution

Using monkeypatch as suggested by @Kound removes the boilerplate code to restore the cwd. You can also enable autouse to automatically apply this fixture to all test functions. Add the following fixture to conftest.py to change the cwd for all tests:

@pytest.fixture(autouse=True)
def change_test_dir(request, monkeypatch):
    monkeypatch.chdir(request.fspath.dirname)

Answer 2

Instead of creating a fixture for each directory like suggested by @DV82XL you can simply use monkeypatch to achieve the same:

import pytest
from pathlib import Path

@pytest.fixture
def base_path() -> Path:
    """Get the current folder of the test"""
    return Path(__file__).parent



def test_something(base_path: Path, monkeypatch: pytest.MonkeyPatch):
    monkeypatch.chdir(base_path / "data" )
    # Do something in the data folder