conftest.py

# Pytest configuration to mark tests as slow
# (this way we can skip them for quicker checks)
# See https://docs.pytest.org/en/latest/example/simple.html#control-skipping-of-tests-according-to-command-line-option
# for the following code to add a marker for slow tests

import pytest

def pytest_addoption(parser):
    parser.addoption(
        "--runslow", 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 config.getoption("--runslow"):
        # --runslow given in cli: do not skip slow tests
        return
    skip_slow = pytest.mark.skip(reason="need --runslow option to run")
    for item in items:
        if "slow" in item.keywords:
            item.add_marker(skip_slow)