diff --git a/zaza/openstack/charm_tests/ceph/tests.py b/zaza/openstack/charm_tests/ceph/tests.py
index e628289..2280879 100644
--- a/zaza/openstack/charm_tests/ceph/tests.py
+++ b/zaza/openstack/charm_tests/ceph/tests.py
@@ -463,7 +463,7 @@ class CephTest(test_utils.OpenStackBaseTest):
 
         The blacklist actions execute and behave as expected.
         """
-        logging.info('Checking blacklist-add-disk and'
+        logging.info('Checking blacklist-add-disk and '
                      'blacklist-remove-disk actions...')
         unit_name = 'ceph-osd/0'
 
@@ -545,6 +545,29 @@ class CephTest(test_utils.OpenStackBaseTest):
         )
         logging.debug('OK')
 
+    def get_num_osds(self, osd):
+        """Compute the number of active OSD's."""
+        result = zaza_model.run_on_unit(osd, 'ceph osd stat --format=json')
+        result = json.loads(result['Stdout'])
+        return int(result['num_osds'])
+
+    def test_cache_device(self):
+        """Test adding a new disk with a caching device."""
+        logging.info('Running add-disk action with a caching device')
+        mon = next(iter(zaza_model.get_units('ceph-mon'))).entity_id
+        osds = [x.entity_id for x in zaza_model.get_units('ceph-osd')]
+        for unit in osds:
+            zaza_model.add_storage(unit, 'cache-devices', 'cinder', 10)
+            loop_dev = zaza_utils.add_loop_device(unit, 10)
+            action_obj = zaza_model.run_action(
+                unit_name=unit,
+                action_name='add-disk',
+                action_params={'osd-devices': loop_dev.get('Stdout'),
+                               'partition-size': 5}
+            )
+            zaza_utils.assertActionRanOK(action_obj)
+        self.assertEqual(len(osds) * 2, self.get_num_osds(mon))
+
 
 class CephRGWTest(test_utils.OpenStackBaseTest):
     """Ceph RADOS Gateway Daemons Test Class."""
diff --git a/zaza/openstack/utilities/generic.py b/zaza/openstack/utilities/generic.py
index a099b13..126ef82 100644
--- a/zaza/openstack/utilities/generic.py
+++ b/zaza/openstack/utilities/generic.py
@@ -723,3 +723,22 @@ def get_leaders_and_non_leaders(application_name):
         else:
             non_leaders.append(unit)
     return leader, non_leaders
+
+
+def add_loop_device(unit, size=10):
+    """Add a loopback device to a Juju unit.
+
+    :param unit: The unit name on which to create the device.
+    :type unit: str
+
+    :param size: The size in GB of the device.
+    :type size: int
+
+    :returns: The device name.
+    """
+    loop_name = '/home/ubuntu/loop.img'
+    truncate = 'truncate --size {}GB {}'.format(size, loop_name)
+    losetup = 'losetup --find {}'.format(loop_name)
+    lofind = 'losetup -a | grep {} | cut -f1 -d ":"'.format(loop_name)
+    cmd = "sudo sh -c '{} && {} && {}'".format(truncate, losetup, lofind)
+    return model.run_on_unit(unit, cmd)