diff --git a/ironic/common/exception.py b/ironic/common/exception.py
index 40a56f95..6c3ad178 100644
--- a/ironic/common/exception.py
+++ b/ironic/common/exception.py
@@ -31,7 +31,7 @@ from oslo.config import cfg
 from ironic.common import safe_utils
 from ironic.openstack.common import excutils
 from ironic.openstack.common import log as logging
-
+from ironic.openstack.common.gettextutils import _
 
 LOG = logging.getLogger(__name__)
 
@@ -234,3 +234,7 @@ class NodeNotFound(NotFound):
 
 class InterfaceNotFound(NotFound):
     message = _("Interface %(iface)s could not be found.")
+
+
+class PowerStateFailure(IronicException):
+    message = _("Failed to set node power state to %(pstate)s.")
diff --git a/ironic/tests/drivers/__init__.py b/ironic/tests/drivers/__init__.py
new file mode 100644
index 00000000..56425d0f
--- /dev/null
+++ b/ironic/tests/drivers/__init__.py
@@ -0,0 +1,16 @@
+# vim: tabstop=4 shiftwidth=4 softtabstop=4
+
+# Copyright 2013 Hewlett-Packard Development Company, L.P.
+# All Rights Reserved.
+#
+#    Licensed under the Apache License, Version 2.0 (the "License"); you may
+#    not use this file except in compliance with the License. You may obtain
+#    a copy of the License at
+#
+#         http://www.apache.org/licenses/LICENSE-2.0
+#
+#    Unless required by applicable law or agreed to in writing, software
+#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+#    License for the specific language governing permissions and limitations
+#    under the License.