diff --git a/test-requirements.txt b/test-requirements.txt
index 460a1e9..2a43527 100644
--- a/test-requirements.txt
+++ b/test-requirements.txt
@@ -15,6 +15,7 @@ testtools>=1.4.0 # MIT
 pifpaf>=0.10.0 # Apache-2.0
 codecov>=1.4.0
 nose>=1.3.7
+pytest
 
 # releasenotes
 reno>=1.8.0 # Apache-2.0
diff --git a/tox.ini b/tox.ini
index 56e02a6..3832c6b 100644
--- a/tox.ini
+++ b/tox.ini
@@ -12,7 +12,7 @@ setenv =
 deps =
    -r{toxinidir}/requirements.txt
    -r{toxinidir}/test-requirements.txt
-commands = python setup.py test --slowest --testr-args='{posargs}'
+commands = py.test -vv {posargs}
 
 [testenv:pep8]
 commands = flake8 {posargs}
@@ -34,16 +34,16 @@ commands =
 commands = python setup.py build_sphinx
 
 [testenv:pypy-etcd]
-commands = {toxinidir}/setup-etcd-env.sh pifpaf -g TOOZ_TEST run etcd -- python setup.py test --slowest --testr-args='{posargs}'
+commands = {toxinidir}/setup-etcd-env.sh pifpaf -g TOOZ_TEST run etcd -- py.test -vv '{posargs}'
 
 [testenv:py27-etcd]
-commands = {toxinidir}/setup-etcd-env.sh pifpaf -g TOOZ_TEST run etcd -- python setup.py test --slowest --testr-args='{posargs}'
+commands = {toxinidir}/setup-etcd-env.sh pifpaf -g TOOZ_TEST run etcd -- py.test -vv '{posargs}'
 
 [testenv:py35-etcd]
-commands = {toxinidir}/setup-etcd-env.sh pifpaf -g TOOZ_TEST run etcd -- python setup.py test --slowest --testr-args='{posargs}'
+commands = {toxinidir}/setup-etcd-env.sh pifpaf -g TOOZ_TEST run etcd -- py.test -vv '{posargs}'
 
 [testenv:py36-etcd]
-commands = {toxinidir}/setup-etcd-env.sh pifpaf -g TOOZ_TEST run etcd -- python setup.py test --slowest --testr-args='{posargs}'
+commands = {toxinidir}/setup-etcd-env.sh pifpaf -g TOOZ_TEST run etcd -- py.test -vv '{posargs}'
 
 [testenv:examples]
 commands = {toxinidir}/setup-etcd-env.sh pifpaf -g TOOZ_TEST run etcd -- python {toxinidir}/etcd3gw/examples/etcd.py