Argthtjtr

My pytest test files are spread across multiple packages, and they share some common fixtures. However, I found that my auto-used session-scoped fixture is ran multiple times.

Here is a basic structure of my project:

.

├── Pipfile

├── Pipfile.lock

├── __init__.py

├── common

│   ├── __init__.py

│   └── conftest.py

├── pkg_a

│   ├── __init__.py

│   ├── conftest.py

│   └── test_a.py

└── pkg_b

    ├── __init__.py

    ├── conftest.py

    └── test_b.py

And here are the content of each .py file:

==> ./__init__.py <==



==> ./common/__init__.py <==



==> ./common/conftest.py <==

import pytest





@pytest.fixture(scope='session', autouse=True)

def setup():

    print 'setting up'

    yield

    print 'tearing down'





==> ./pkg_a/__init__.py <==



==> ./pkg_a/conftest.py <==

from common.conftest import *



==> ./pkg_a/test_a.py <==

def test():

    assert True



==> ./pkg_b/__init__.py <==



==> ./pkg_b/conftest.py <==

from common.conftest import *



==> ./pkg_b/test_b.py <==

def test_b():

    assert True

Here is the output of pytest:

➜ pytest -s pkg_a pkg_b

========================== test session starts ==========================

platform darwin -- Python 2.7.15, pytest-3.10.0, py-1.7.0, pluggy-0.8.0

rootdir: /path/to/the/project, inifile:

collected 2 items



pkg_a/test_a.py setting up

.

pkg_b/test_b.py setting up

.tearing down

tearing down





======================= 2 passed in 0.02 seconds ========================

My understanding to the session fixtures is that they will only be ran once for the lifetime of pytest command. But here the setting up and tearing down are printed twice, and they are interleaved.

Is there any way to only execute the fixture only once? I want the setting up to be printed only once at the beginning and tearing down at the very end for the whole test session.

P.S. I know the parameterized session fixture will be execute multiple times. But I don't think my fixture is parameterized.

You are right. Session scoped fixture is supposed to run only once. But if you look closely, there are two setup fixtures for test_a. One from common/conftest.py and other from pkg_a/conftest.py. You don't need to import common.conftest.py in pkg_a/conftest.py. pytest starts collecting conftest files starting from project root.
You can see the fixture setup process with --setup-show switch: pytest test_a.py --setup-show.

To solve your problem, you can remove from common.conftest import * from your test_a(b)/conftest.py files .

More about conftest collection of pytest here: https://docs.pytest.org/en/2.7.3/plugins.html