diff --git a/roles/run-tempest/README.rst b/roles/run-tempest/README.rst
index 001586e..b5defb7 100644
--- a/roles/run-tempest/README.rst
+++ b/roles/run-tempest/README.rst
@@ -16,9 +16,19 @@
    :default: ''
 
    A regular expression used to select the tests.
+
    It works only when used with some specific tox environments
    ('all', 'all-plugin'.)
 
+   Multi-line and commented regexs can be achieved by doing this:
+
+       ::
+           vars:
+             tempest_test_regex: |
+               (?x)    # Ignore comments and whitespaces
+               # Line with only a comment.
+               (tempest\.(api|scenario|thirdparty)).*$    # Run only api scenario and third party
+
 .. zuul:rolevar:: tox_venvlist
    :default: smoke
 
diff --git a/tempest/api/object_storage/test_container_sync.py b/tempest/api/object_storage/test_container_sync.py
index 042d288..2e979bc 100644
--- a/tempest/api/object_storage/test_container_sync.py
+++ b/tempest/api/object_storage/test_container_sync.py
@@ -33,8 +33,6 @@
 
 
 class ContainerSyncTest(base.BaseObjectTest):
-    clients = {}
-
     credentials = [['operator', CONF.object_storage.operator_role],
                    ['operator_alt', CONF.object_storage.operator_role]]
 
@@ -54,6 +52,7 @@
         super(ContainerSyncTest, cls).resource_setup()
         cls.containers = []
         cls.objects = []
+        cls.clients = {}
 
         # Default container-server config only allows localhost
         cls.local_ip = '127.0.0.1'
diff --git a/tempest/api/volume/test_volumes_list.py b/tempest/api/volume/test_volumes_list.py
index b5f98ea..6294994 100644
--- a/tempest/api/volume/test_volumes_list.py
+++ b/tempest/api/volume/test_volumes_list.py
@@ -26,8 +26,8 @@
 
 
 class VolumesListTestJSON(base.BaseVolumeTest):
-    # NOTE: This test creates a number of 1G volumes. To run successfully,
-    # ensure that the backing file for the volume group that Nova uses
+    # NOTE: This test creates a number of 1G volumes. To run it successfully,
+    # ensure that the backing file for the volume group that Cinder uses
     # has space for at least 3 1G volumes!
     # If you are running a Devstack environment, ensure that the
     # VOLUME_BACKING_FILE_SIZE is at least 4G in your localrc