1.6.0: pytest is failing

I'm trying to package your module as rpm packag. So I'm using typical in such case build, install and test cycle used on building package from non-root account:

• "setup.py build"
• "setup.py install --root </install/prefix>"
• "pytest with PYTHONPATH pointing to sitearch and sitelib inside </install/prefix>

May I ask for help because few units are failing:

+ PYTHONPATH=/home/tkloczko/rpmbuild/BUILDROOT/python-cloudpickle-1.6.0-6.fc35.x86_64/usr/lib64/python3.8/site-packages:/home/tkloczko/rpmbuild/BUILDROOT/python-cloudpickle-1.6.0-6.fc35.x86_64/usr/lib/python3.8/site-packages
+ /usr/bin/pytest -ra --import-mode=importlib
=========================================================================== test session starts ============================================================================
platform linux -- Python 3.8.11, pytest-6.2.4, py-1.10.0, pluggy-0.13.1
benchmark: 3.4.1 (defaults: timer=time.perf_counter disable_gc=False min_rounds=5 min_time=0.000005 max_time=1.0 calibration_precision=10 warmup=False warmup_iterations=100000)
Using --randomly-seed=739258526
rootdir: /home/tkloczko/rpmbuild/BUILD/cloudpickle-1.6.0, configfile: tox.ini
plugins: forked-1.3.0, shutil-1.7.0, virtualenv-1.7.0, expect-1.1.0, flake8-1.0.7, timeout-1.4.2, betamax-0.8.1, freezegun-0.4.2, aspectlib-1.5.2, toolbox-0.5, rerunfailures-9.1.1, requests-mock-1.9.3, cov-2.12.1, pyfakefs-4.5.0, flaky-3.7.0, benchmark-3.4.1, xdist-2.3.0, pylama-7.7.1, datadir-1.3.1, regressions-2.2.0, cases-3.6.3, xprocess-0.18.1, black-0.3.12, anyio-3.3.0, asyncio-0.15.1, trio-0.7.0, httpbin-1.0.0, subtests-0.5.0, isort-2.0.0, hypothesis-6.14.6, mock-3.6.1, profiling-1.7.0, randomly-3.8.0, Faker-8.12.1
collected 7 items / 2 errors / 5 selected

================================================================================== ERRORS ==================================================================================
________________________________________________________________ ERROR collecting tests/cloudpickle_test.py ________________________________________________________________
ImportError while importing test module '/home/tkloczko/rpmbuild/BUILD/cloudpickle-1.6.0/tests/cloudpickle_test.py'.
Hint: make sure your test modules/packages have valid Python names.
Traceback:
tests/cloudpickle_test.py:52: in <module>
    from .testutils import subprocess_pickle_echo
E   ImportError: attempted relative import with no known parent package
______________________________________________________________ ERROR collecting tests/test_backward_compat.py ______________________________________________________________
ImportError while importing test module '/home/tkloczko/rpmbuild/BUILD/cloudpickle-1.6.0/tests/test_backward_compat.py'.
Hint: make sure your test modules/packages have valid Python names.
Traceback:
tests/test_backward_compat.py:17: in <module>
    from .generate_old_pickles import PICKLE_DIRECTORY
E   ImportError: attempted relative import with no known parent package
========================================================================= short test summary info ==========================================================================
ERROR tests/cloudpickle_test.py
ERROR tests/test_backward_compat.py
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! Interrupted: 2 errors during collection !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
============================================================================ 2 errors in 0.49s =============================================================================
pytest-xprocess reminder::Be sure to terminate the started process by running 'pytest --xkill' if you have not explicitly done so in your fixture with 'xprocess.getinfo(<process_name>).terminate()'.