-r common.txt
flake8==2.4.1
pytest==2.7.2
coverage==4.0b1
pytest-cover==3.0.0
pytest-django==2.8.0
mock==1.3.0

-r common.txt
flake8==2.4.1
pytest==2.7.2
coverage==4.0b1
pytest-cover==3.0.0
pytest-django==2.8.0
mock==1.3.0
tox==2.1.1

Add tox to test requirements file
Add tox to test requirements file
