Autouse fixtures in Packages (__init__.py)

[nicoddemus]

Autouse fixtures defined in package __init__.py files are not being executed for tests under the package.

Consider:

# content of pkg/__init__.py
import pytest

values = []

@pytest.fixture(scope="module", autouse=True)
def startup():
    values.append("started")

# content of pkg/test_x.py
from . import values

def test_x():
    assert values == ['started']

This fails because startup() is never called.

If however we replace startup by a xunit-style setup_module function:

# content of pkg/__init__.py
import pytest

values = []

# @pytest.fixture(scope="module", autouse=True)
# def startup():
#     values.append("started")

def setup_module():
    values.append("started")

Then the test passes.

Discovered this bug while working on #3094. 😬

As discussed below, we have to discuss if this is a bug or not.

[nicoddemus]

Looking at the code, I'm not so sure if this is a bug or just how things are intended to work.

setup_module gets called because after the package gets collected setup_module and teardown_module will be called on it because of how SetupState works.

But for fixtures we don't have the same guarantees, as fixtures that are meant to be shared are supposed to go into conftest files instead.

To fix this will mean to make autouse fixtures in packages to apply to all test modules under it, like a conftest.py file would.

@RonnyPfannschmidt thoughts?

[RonnyPfannschmidt]

@nicoddemus structurally we simply never had packages share structural locations with test files

i beleive we need to take a close look on what should go to conftest, package and how things interact, and then deprecate some things harshly

our life cycle policies are unable to adequately handle the issue at hand, its going to be a mess

[nicoddemus]

OK, so I will go on with #3094 (I can workaround this) and defer this discussion for later.

[blacklight]

I'm bumping into this issue a few years later. I agree that workarounds can be found, but this isn't the way things are expected to work. If everything in the tests' root __init__.py gets executed before the tests, then autouse=True fixtures should also be included.