[tox]
envlist = py26, py27, py32, py33, py34, pypy

[testenv]
deps = -r{toxinidir}/dev_requirements.txt
       nose
commands = nosetests {posargs}

[tox]
envlist = py34, py33, py32, py27, pypy, py26

[testenv]
deps = -r{toxinidir}/dev_requirements.txt
       nose
commands = nosetests {posargs}

Tweak tested Python versions to do Python 3 first
Tweak tested Python versions to do Python 3 first

Somewhat pointless, but this way runs will count as Python 3 uses and not Python 2 in PyPI logs.