Remove usage of setup.py test
In [1] a deprecation warning was added to remove test. Altought we are using tox, currently tox is calling directly setup.py which still emit the warning.
We should probably modify tox command:
commands = {envpython} -m unittest discover
This will avoid the instalation of external dependencies for just running the test.
[1] https://github.com/pypa/setuptools/commit/cd84510713ada48bf33d4efa749c2952e3fc1a49