conftest.py

# pytest configuration

import pytest


def pytest_addoption(parser):
    parser.addoption(
        "--run-slow", action="store_true", default=False, help="run slow tests"
    )


def pytest_configure(config):
    config.addinivalue_line("markers", "slow: mark test as slow to run")


def pytest_collection_modifyitems(config, items):
    if not config.getoption("--run-slow"):
        # without --run-slow option: skip all slow tests
        skip_slow = pytest.mark.skip(reason="need --run-slow option to run")
        for item in items:
            if "slow" in item.keywords:
                item.add_marker(skip_slow)


@pytest.fixture
def anyio_backend():
    return "asyncio"