tests/conftest.py

#
# For licensing see accompanying LICENSE file.
# Copyright (C) 2020 Apple Inc. All Rights Reserved.
#
"""Configuration for pytest."""

from typing import Dict, Tuple

import pytest

# store history of failures per test class name and per index in parametrize (if parametrize used)
_test_failed_incremental: Dict[str, Dict[Tuple[int, ...], str]] = {}


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)


# The two hooks below implement "incremental testing"
# If one step fails, further steps are not continued
# The code is from the pytest docs: https://docs.pytest.org/en/latest/example/simple.html

def pytest_runtest_makereport(item, call):
    if 'incremental' in item.keywords:
        # incremental marker is used
        if call.excinfo is not None:
            # the test has failed
            # retrieve the class name of the test
            cls_name = str(item.cls)
            # retrieve the index of the test
            # (if parametrize is used in combination with incremental)
            parametrize_index = (
                tuple(item.callspec.indices.values())
                if hasattr(item, 'callspec')
                else ()
            )
            # retrieve the name of the test function
            test_name = item.originalname or item.name
            # store in _test_failed_incremental the original name of the failed test
            _test_failed_incremental.setdefault(cls_name, {}).setdefault(
                parametrize_index, test_name
            )


def pytest_runtest_setup(item):
    if 'incremental' in item.keywords:
        # retrieve the class name of the test
        cls_name = str(item.cls)
        # check if a previous test has failed for this class
        if cls_name in _test_failed_incremental:
            # retrieve the index of the test
            # (if parametrize is used in combination with incremental)
            parametrize_index = (
                tuple(item.callspec.indices.values())
                if hasattr(item, 'callspec')
                else ()
            )
            # retrieve the name of the first test function to fail for this class name and index
            test_name = _test_failed_incremental[cls_name].get(parametrize_index, None)
            # if name found, test has failed for the combination of class name & test name
            if test_name is not None:
                pytest.xfail('previous test failed ({})'.format(test_name))