diff --git a/tox.ini b/tox.ini
index 3c325ddb7..1ee6e4bff 100644
--- a/tox.ini
+++ b/tox.ini
@@ -63,7 +63,7 @@ setenv =
     AMQP1_BACKEND=qpidd
     ENVNAME={envname}
     WORKDIR={toxworkdir}
-commands = {toxinidir}/setup-test-env-amqp1.sh python setup.py testr --slowest --testr-args='oslo_messaging.tests.functional'
+commands = {toxinidir}/setup-test-env-amqp1.sh python setup.py testr --slowest --testr-args='{posargs:oslo_messaging.tests.functional}'
 
 [testenv:py35-func-amqp1]
 basepython = python3.5
@@ -73,7 +73,7 @@ setenv =
     AMQP1_BACKEND=qpidd
     ENVNAME={envname}
     WORKDIR={toxworkdir}
-commands = {toxinidir}/setup-test-env-amqp1.sh python setup.py testr --slowest --testr-args='oslo_messaging.tests.functional'
+commands = {toxinidir}/setup-test-env-amqp1.sh python setup.py testr --slowest --testr-args='{posargs:oslo_messaging.tests.functional}'
 
 [testenv:py27-func-zmq]
 commands = {toxinidir}/setup-test-env-zmq.sh python setup.py testr --slowest --testr-args='{posargs:oslo_messaging.tests.functional}'