Pytest setup
You will need to install pytest before you can use it. It should be added as a development-time dependency of the project.
Python 2
virtualenv venv
source venv/bin/activate
pip install pytest
Python 3
virtualenv venv -p python3
source venv/bin/activate
pip install pytest
Python 3 Debian/Ubuntu
apt-get install python3-pytest
Python 3 RedHat/Centos
yum install python3-pytest