```
$ pifpaf run postgresql -- pytest
WARNING [pifpaf.drivers] `psutil.Popen(pid=23360, status='terminated')` is already gone, sending SIGKILL to its process group
ERROR [pifpaf] sequence item 0: expected str instance, bytes found
```

```
$ tox -v --recreate
using tox.ini: /home/tony/work/inria/repo/swh/swh-environment/swh-deposit/tox.ini
using tox-3.6.0 from /home/tony/work/inria/repo/swh/swh-environment/.venv/lib/python3.7/site-packages/tox/__init__.py
GLOB sdist-make: /home/tony/work/inria/repo/swh/swh-environment/swh-deposit/setup.py
  /home/tony/work/inria/repo/swh/swh-environment/swh-deposit$ /home/tony/work/inria/repo/swh/swh-environment/.venv/bin/python3 /home/tony/work/inria/repo/swh/swh-environment/swh-deposit/setup.py sdist --formats=zip --dist-dir /home/tony/work/inria/repo/swh/swh-environment/swh-deposit/.tox/dist >/home/tony/work/inria/repo/swh/swh-environment/swh-deposit/.tox/log/tox-0.log
package .tmp/package/1/swh.deposit-0.0.63.post25.zip links to dist/swh.deposit-0.0.63.post25.zip (/home/tony/work/inria/repo/swh/swh-environment/swh-deposit/.tox)
flake8 cannot reuse: -r flag
flake8 recreate: /home/tony/work/inria/repo/swh/swh-environment/swh-deposit/.tox/flake8
  /home/tony/work/inria/repo/swh/swh-environment/swh-deposit/.tox$ /home/tony/work/inria/repo/swh/swh-environment/.venv/bin/python3 -m virtualenv --python /home/tony/work/inria/repo/swh/swh-environment/.venv/bin/python3 flake8 >/home/tony/work/inria/repo/swh/swh-environment/swh-deposit/.tox/flake8/log/flake8-0.log
flake8 installdeps: flake8
WARNING: Discarding $PYTHONPATH from environment, to override specify PYTHONPATH in 'passenv' in your configuration.
  /home/tony/work/inria/repo/swh/swh-environment/swh-deposit$ /home/tony/work/inria/repo/swh/swh-environment/swh-deposit/.tox/flake8/bin/python -m pip install flake8 >/home/tony/work/inria/repo/swh/swh-environment/swh-deposit/.tox/flake8/log/flake8-1.log
write config to /home/tony/work/inria/repo/swh/swh-environment/swh-deposit/.tox/flake8/.tox-config1 as '25938b25ec3de7826eb2da22856c9001 /home/tony/work/inria/repo/swh/swh-environment/.venv/bin/python3\n3.6.0 0 0 0\n00000000000000000000000000000000 flake8'
  /home/tony/work/inria/repo/swh/swh-environment/swh-deposit$ /home/tony/work/inria/repo/swh/swh-environment/swh-deposit/.tox/flake8/bin/python -m pip freeze >/home/tony/work/inria/repo/swh/swh-environment/swh-deposit/.tox/flake8/log/flake8-2.log
flake8 installed: flake8==3.6.0,mccabe==0.6.1,pycodestyle==2.4.0,pyflakes==2.0.0,swh.deposit==0.0.63.post25
flake8 run-test-pre: PYTHONHASHSEED='827885568'
flake8 runtests: commands[0] | /home/tony/work/inria/repo/swh/swh-environment/swh-deposit/.tox/flake8/bin/python -m flake8 '--exclude=.tox,.git,__pycache__,.tox,.eggs,*.egg,swh/deposit/migrations'
  /home/tony/work/inria/repo/swh/swh-environment/swh-deposit$ /home/tony/work/inria/repo/swh/swh-environment/swh-deposit/.tox/flake8/bin/python -m flake8 '--exclude=.tox,.git,__pycache__,.tox,.eggs,*.egg,swh/deposit/migrations'
py3 cannot reuse: -r flag
py3 recreate: /home/tony/work/inria/repo/swh/swh-environment/swh-deposit/.tox/py3
  /home/tony/work/inria/repo/swh/swh-environment/swh-deposit/.tox$ /home/tony/work/inria/repo/swh/swh-environment/.venv/bin/python3 -m virtualenv --python /home/tony/work/inria/repo/swh/swh-environment/.venv/bin/python3 py3 >/home/tony/work/inria/repo/swh/swh-environment/swh-deposit/.tox/py3/log/py3-0.log
py3 installdeps: .[testing], pytest-cov, pifpaf, pytest-django
  /home/tony/work/inria/repo/swh/swh-environment/swh-deposit$ /home/tony/work/inria/repo/swh/swh-environment/swh-deposit/.tox/py3/bin/python -m pip install '.[testing]' pytest-cov pifpaf pytest-django >/home/tony/work/inria/repo/swh/swh-environment/swh-deposit/.tox/py3/log/py3-1.log
py3 inst: /home/tony/work/inria/repo/swh/swh-environment/swh-deposit/.tox/.tmp/package/1/swh.deposit-0.0.63.post25.zip
write config to /home/tony/work/inria/repo/swh/swh-environment/swh-deposit/.tox/py3/.tox-config1 as '25938b25ec3de7826eb2da22856c9001 /home/tony/work/inria/repo/swh/swh-environment/.venv/bin/python3\n3.6.0 0 0 0\n00000000000000000000000000000000 .[testing]\n00000000000000000000000000000000 pytest-cov\n00000000000000000000000000000000 pifpaf\n00000000000000000000000000000000 pytest-django'
  /home/tony/work/inria/repo/swh/swh-environment/swh-deposit$ /home/tony/work/inria/repo/swh/swh-environment/swh-deposit/.tox/py3/bin/python -m pip install --exists-action w /home/tony/work/inria/repo/swh/swh-environment/swh-deposit/.tox/.tmp/package/1/swh.deposit-0.0.63.post25.zip >/home/tony/work/inria/repo/swh/swh-environment/swh-deposit/.tox/py3/log/py3-2.log
  /home/tony/work/inria/repo/swh/swh-environment/swh-deposit$ /home/tony/work/inria/repo/swh/swh-environment/swh-deposit/.tox/py3/bin/python -m pip freeze >/home/tony/work/inria/repo/swh/swh-environment/swh-deposit/.tox/py3/log/py3-3.log
py3 installed: aiohttp==3.4.4,amqp==2.3.2,arrow==0.12.1,async-timeout==3.0.1,atomicwrites==1.2.1,attrs==18.2.0,billiard==3.5.0.5,celery==4.2.1,certifi==2018.11.29,cffi==1.11.5,chardet==3.0.4,Click==7.0,coverage==4.5.2,daiquiri==1.5.0,Django==1.11.17,djangorestframework==3.9.0,elasticsearch==6.3.1,extras==1.0.0,fixtures==3.0.0,Flask==1.0.2,idna==2.8,itsdangerous==1.1.0,Jinja2==2.10,kombu==4.2.2,linecache2==1.0.0,MarkupSafe==1.1.0,more-itertools==4.3.0,msgpack-python==0.5.6,multidict==4.5.2,pbr==5.1.1,pifpaf==2.2.1,pluggy==0.8.0,psutil==5.4.8,psycopg2==2.7.6.1,py==1.7.0,pycparser==2.19,pytest==4.0.2,pytest-cov==2.6.0,pytest-django==3.4.4,python-dateutil==2.7.5,python-mimeparse==1.6.0,pytz==2018.7,PyYAML==3.13,requests==2.21.0,retrying==1.3.3,six==1.12.0,swh.core==0.0.49,swh.deposit==0.0.63.post25,swh.loader.core==0.0.38,swh.loader.dir==0.0.33,swh.loader.tar==0.0.37,swh.model==0.0.29,swh.objstorage==0.0.28,swh.scheduler==0.0.38,swh.storage==0.0.117,systemd-python==234,testtools==2.3.0,traceback2==1.4.0,unittest2==1.1.0,urllib3==1.24.1,vcversioner==2.16.0.0,vine==1.1.4,Werkzeug==0.14.1,xattr==0.9.6,xmltodict==0.11.0,yarl==1.3.0
py3 run-test-pre: PYTHONHASHSEED='827885568'
py3 runtests: commands[0] | pifpaf run postgresql -- pytest --cov /home/tony/work/inria/repo/swh/swh-environment/swh-deposit/.tox/py3/lib/python3.7/site-packages/swh/deposit --cov-branch /home/tony/work/inria/repo/swh/swh-environment/swh-deposit/.tox/py3/lib/python3.7/site-packages/swh/deposit
  /home/tony/work/inria/repo/swh/swh-environment/swh-deposit$ /home/tony/work/inria/repo/swh/swh-environment/swh-deposit/.tox/py3/bin/pifpaf run postgresql -- pytest --cov /home/tony/work/inria/repo/swh/swh-environment/swh-deposit/.tox/py3/lib/python3.7/site-packages/swh/deposit --cov-branch /home/tony/work/inria/repo/swh/swh-environment/swh-deposit/.tox/py3/lib/python3.7/site-packages/swh/deposit
WARNING [pifpaf.drivers] `psutil.Popen(pid=29739, status='terminated')` is already gone, sending SIGKILL to its process group
ERROR [pifpaf] sequence item 0: expected str instance, bytes found
ERROR: InvocationError for command '/home/tony/work/inria/repo/swh/swh-environment/swh-deposit/.tox/py3/bin/pifpaf run postgresql -- pytest --cov /home/tony/work/inria/repo/swh/swh-environment/swh-deposit/.tox/py3/lib/python3.7/site-packages/swh/deposit --cov-branch /home/tony/work/inria/repo/swh/swh-environment/swh-deposit/.tox/py3/lib/python3.7/site-packages/swh/deposit' (exited with code 1)
___________________________________________________________________________________________ summary ___________________________________________________________________________________________
  flake8: commands succeeded
ERROR:   py3: commands failed
```