conftest.py

'''
Local per-directory pytest plugins. See https://docs.pytest.org/en/2.7.3/plugins.html

The argument "runslow" provides the option to ignore tests marked as 
"slow" when running the pytest suite. 
See https://docs.pytest.org/en/latest/example/simple.html for more information.
'''

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)