Override native toml (`[tool.pytest_env]`) with (pytest.ini) configuration in sub dir

[bram-tv]

A summary of our use case:

• we have tests in a tests/ directory which requires a certain set of ENV vars
• we have tests in a tests_integration directory which requires a different set of ENV vars

We are also using poetry in combination with the pyproject.toml file and when using poetry run pytest it runs the tests in tests/ directory and when using poetry run pytest tests_integration/ it runs the tests in the tests_integration directory.

Let's start with a concrete example of what we want and what currently works.

pyproject.toml

[tool.pytest.ini_options]
addopts = ["-v"]
pythonpath = ["src"]
testpaths = ["tests"]
env = [
    "TEST_ENV=unit",
]

tests/tests_env.py:

from os import environ

def test_env():
    assert environ.get("TEST_ENV", "") == "unit"

tests_integration/test_env.py:

from os import environ

def test_env():
    assert environ.get("TEST_ENV", "") == "integration"

tests_integration/pytest.ini:

[pytest]
addopts = -v
env =
    TEST_ENV=integration

Running it:

$ poetry run pytest
...
tests/test_env.py::test_env PASSED                                                                             [100%]
...
$ poetry run pytest tests
...
tests/test_env.py::test_env PASSED                                                                             [100%]
...
$ poetry run pytest tests_integration/
...
tests_integration/test_env.py::test_env PASSED                                                                 [100%]

The above is working how we want it to work.

Moving to the native toml syntax for pytest-env: pyproject.toml changed to:

[tool.pytest.ini_options]
addopts = ["-v"]
pythonpath = ["src"]
testpaths = ["tests"]

[tool.pytest_env]
TEST_ENV = "unit"

rest of the files kept as-is

Running again:

$ poetry run pytest
...
tests/test_env.py::test_env PASSED                                                                             [100%]
$ poetry run pytest tests
...
tests/test_env.py::test_env PASSED                                                                             [100%]
$ poetry run pytest tests_integration/
...
tests_integration/test_env.py::test_env FAILED                                                                 [100%]

======================================================= FAILURES =======================================================
_______________________________________________________ test_env _______________________________________________________

    def test_env():
>       assert environ.get("TEST_ENV", "") == "integration"
E       AssertionError: assert 'unit' == 'integration'
E         - integration
E         + unit

tests_integration/test_env.py:4: AssertionError

What we're looking for is to be able to:

• use the native toml syntax (since that is cleaner)
• override the environment variables in a sub-dir (doesn't have to be via pytest.ini, other mechansims could also work)

(An accepted/expected limitation in the above is that pytest will never run tests/ and tests_integration/ at the same time/in the same process)