diff --git a/TESTING.rst b/TESTING.rst
index 6e1d3a287af..198ae81ba0a 100644
--- a/TESTING.rst
+++ b/TESTING.rst
@@ -502,6 +502,10 @@ or::
       $ tox -e py27 neutron.tests.unit.test_manager.NeutronManagerTestCase
       $ tox -e py27 neutron.tests.unit.test_manager.NeutronManagerTestCase.test_service_plugin_is_loaded
 
+If you want to pass other arguments to ostestr, you can do the following::
+      $ tox -e -epy27 -- --regex neutron.tests.unit.test_manager --serial
+
+
 Coverage
 --------
 
diff --git a/tools/ostestr_compat_shim.sh b/tools/ostestr_compat_shim.sh
new file mode 100755
index 00000000000..a483ed1a1ef
--- /dev/null
+++ b/tools/ostestr_compat_shim.sh
@@ -0,0 +1,8 @@
+#!/bin/sh
+
+# preserve old behavior of using an arg as a regex when '--' is not present
+case $@ in
+  (*--*) ostestr $@;;
+  ('') ostestr;;
+  (*) ostestr --regex "$@"
+esac
diff --git a/tox.ini b/tox.ini
index 8a853c3b56d..faecce1d2e1 100644
--- a/tox.ini
+++ b/tox.ini
@@ -15,7 +15,7 @@ deps = -r{toxinidir}/requirements.txt
 whitelist_externals = sh
 commands =
   dsvm-functional: {toxinidir}/tools/deploy_rootwrap.sh {toxinidir} {envdir}/etc {envdir}/bin
-  ostestr --regex '{posargs}'
+  {toxinidir}/tools/ostestr_compat_shim.sh {posargs}
 # there is also secret magic in ostestr which lets you run in a fail only
 # mode. To do this define the TRACE_FAILONLY environmental variable.