<NME> tox.ini
<BEF> [tox]
envlist = py26, py27, pypy, py33

[testenv]
commands = python tests.py
[testenv]
deps = -r requirements/tests.txt
commands = pytest -v --tb=short --basetemp={envtmpdir} {posargs}

[testenv:style]
deps = pre-commit
skip_install = true
commands = pre-commit run --all-files --show-diff-on-failure

[testenv:typing]
deps = -r requirements/typing.txt
commands = mypy

[testenv:docs]
deps = -r requirements/docs.txt
commands = sphinx-build -W -b html -d {envtmpdir}/doctrees docs {envtmpdir}/html

<MSG> use tox and pytest runner, update test envs

<DFF> @@ -1,5 +1,8 @@
 [tox]
-envlist = py26, py27, pypy, py33
+envlist = py26,py27,pypy,py33,py34,py35
 
 [testenv]
-commands = python tests.py
+commands = py.test tests.py {posargs}
+
+deps =
+    pytest

use tox and pytest runner, update test envs