diff --git a/test-requirements.txt b/test-requirements.txt
index 5577c7a8..40087a7e 100644
--- a/test-requirements.txt
+++ b/test-requirements.txt
@@ -1,5 +1,6 @@
 mock
 hacking>=0.9.2,<0.10
 testrepository>=0.0.18
-testtools>=0.9.36,!=1.2.0
+testtools>=1.4.0 # MIT
+os-testr>=0.4.1 # Apache-2.0
 ddt
diff --git a/tox.ini b/tox.ini
index 2c823c95..a864a6d9 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,15 +1,16 @@
 [tox]
-envlist = py27,pep8,py34
+envlist = py34,py27,pep8
 
 [testenv]
 usedevelop = True
 install_command = pip install -U {opts} {packages}
-deps =
-  -r{toxinidir}/requirements.txt
-  -r{toxinidir}/test-requirements.txt
-commands =
-  bash -c "TESTS_DIR=./proliantutils/tests/ python setup.py testr --slowest --testr-args='{posargs}'"
-whitelist_externals = bash
+setenv = VIRTUAL_ENV={envdir}
+         PYTHONDONTWRITEBYTECODE = 1
+         LANGUAGE=en_US
+         LC_ALL=en_US.UTF-8
+         TESTS_DIR=./proliantutils/tests/
+deps = -r{toxinidir}/test-requirements.txt
+commands = ostestr {posargs}
 
 [testenv:pep8]
 basepython = python2.7