How to use pytest.fixture in pytest.hookspec.pytest_configure

[lixianwen]

ENV:

CentOS Linux release 7.8.2003 (Core)
Python 3.6.8
pytest 6.2.5
attrs 20.3.0
iniconfig 1.1.1
packaging 21.3
pluggy 1.0.0
py 1.11.0
tomli 1.2.3
colorama 0.4.4
importlib-metadata4.8.3

Hi, I want to store some global variables shared in difference test case. So I found this question which mention this hook pytest_configure defined in conftest.py.

Actually I want to create some data to database and then bind to pytest, I try to use another fixture in pytest_configure, but it doesn't work.

Here is my snippet in conftest.py:

import pytest

from some_models import User


@pytest.fixture(scope="function")
def db_session(db, request):
    """Creates a new database session for a test."""
    # It's a bussiness code written by colleague, I have to hide it without permission.
    # `db` is a :class:`flask_sqlalchemy.SQLAlchemy` instance.
    # This fixture yield a db.session, so in test function, we call it like that: `db_session.add`.

def pytest_configure(config):
    user = User(name='admin')
    db_session.add(user)
    print('config>>>>>>>>>', config)
    pytest.aio_user = user

When a I run a test function, it raise:

(envaio) [airflow@aioserver-30151 aio]$ pytest -s /home/airflow/aio/tests/api/v2/event/test_create_event.py
[2022-01-30 17:34:50,883] INFO [root.<module>:36] flask env:production
INTERNALERROR> Traceback (most recent call last):
INTERNALERROR>   File "/home/airflow/envaio/lib64/python3.6/site-packages/_pytest/main.py", line 265, in wrap_session
INTERNALERROR>     config._do_configure()
INTERNALERROR>   File "/home/airflow/envaio/lib64/python3.6/site-packages/_pytest/config/__init__.py", line 982, in _do_configure
INTERNALERROR>     self.hook.pytest_configure.call_historic(kwargs=dict(config=self))
INTERNALERROR>   File "/home/airflow/envaio/lib64/python3.6/site-packages/pluggy/_hooks.py", line 277, in call_historic
INTERNALERROR>     res = self._hookexec(self.name, self.get_hookimpls(), kwargs, False)
INTERNALERROR>   File "/home/airflow/envaio/lib64/python3.6/site-packages/pluggy/_manager.py", line 80, in _hookexec
INTERNALERROR>     return self._inner_hookexec(hook_name, methods, kwargs, firstresult)
INTERNALERROR>   File "/home/airflow/envaio/lib64/python3.6/site-packages/pluggy/_callers.py", line 60, in _multicall
INTERNALERROR>     return outcome.get_result()
INTERNALERROR>   File "/home/airflow/envaio/lib64/python3.6/site-packages/pluggy/_result.py", line 60, in get_result
INTERNALERROR>     raise ex[1].with_traceback(ex[2])
INTERNALERROR>   File "/home/airflow/envaio/lib64/python3.6/site-packages/pluggy/_callers.py", line 39, in _multicall
INTERNALERROR>     res = hook_impl.function(*args)
INTERNALERROR>   File "/home/airflow/aio/tests/conftest.py", line 149, in pytest_configure
INTERNALERROR>     db_session.add(user)
INTERNALERROR> AttributeError: 'function' object has no attribute 'add'

Q1: What is the best practice to share global variables between tests?

Q2: If my way is right, how to implement it?

Q3: What is conftest files mention in pytest_configure API document

Thank you for watching this question. Any help is appreciative.

[nicoddemus]

If you want to share data between tests, fixtures are usually used, not hooks.

When databases are involved usually users define a session-scoped fixture which setups the database, and function-scoped fixtures which setup the database for some tests (usually with a rollback mechanism so tests using that fixture leave the database pristine).

Some articles describing the pattern:

• https://itnext.io/setting-up-transactional-tests-with-pytest-and-sqlalchemy-b2d726347629
• https://www.mybluelinux.com/database-integration-tests-with-pytest-sqlalchemy-and-factory-boy-with-faker/
• https://aalvarez.me/posts/python-transactional-tests-using-sqlalchemy-pytest-and-factory-boy/

Hope this helps!

[lixianwen]

Thank you!

According to About fixtures, it mention about whit is fixture and what it can do.

As your word, fixture is quite suitable for my need. I mock dataset in fixture, register fixture in root conftest.py, and then use it in my test case by passing in as a param.

Here is my snippet:
my struct

tests
├── api
│   └── v2
│       ├── event
│       │   ├── __init__.py
│       │   └── test_create_event.py
│       ├── __init__.py
├── conftest.py
├── __init__.py
├── mock_data_fixtures
│   ├── node.py

conftest.py

pytest_plugins = (
    'tests.mock_data_fixtures.node',
)

node.py

import pytest
from factory.fuzzy import FuzzyText

from aio.models import Node


@pytest.fixture
def create_node(db_session):
    node_db_username = FuzzyText(length=8).fuzz()
    node_db_passwd = FuzzyText(length=10).fuzz()
    node = Node(
        db_type="oracle",
        node_db_username=node_db_username,
        node_db_passwd=node_db_passwd,
        node_os_port="22",
        is_valid=1
    )
    db_session.add(node)
    db_session.commit()

    return node.id

test_create_event.py

def test_fetch_node_detail(create_node, db_session):
    node = db_session.query(Node).get(create_node)
    assert node
    assert node.is_valid

[notamonad]

What about a use case where I would like to allow specification of custom log directory path based on a fixture value that in turns gets populated based on CLI option input? Fixture is used as one fixture for all test suite to write test artifacts to (Selenium screenshots, container logs, pickle dumps, packet capture), but also want to dump pytest's logs to it too but with with increased verbosity, so stdout gets INFO, but file logs are DEBUG

there is an example of that in one of github discussions about having better documentation for set_log_path

def pytest_configure(config, artifact_dir):
    log_name = "custom log name here"
    log_path = artifact_dir / "logs"
    log_path.mkdir(exist_ok=True)

    logging_plugin = config.pluginmanager.get_plugin("logging-plugin")
    logging_plugin.set_log_path(str(log_path / log_name))

would be nice to have access to artifact_dir fixture