diff --git a/tobiko/__init__.py b/tobiko/__init__.py
index c92669274..7e9330edd 100644
--- a/tobiko/__init__.py
+++ b/tobiko/__init__.py
@@ -15,7 +15,7 @@ from __future__ import absolute_import
 from tobiko.common.managers import fixture
 from tobiko.common.managers import testcase as testcase_manager
 from tobiko.common.managers import loader as loader_manager
-
+from tobiko.common import exceptions
 
 load_object = loader_manager.load_object
 load_module = loader_manager.load_module
@@ -32,3 +32,6 @@ setup_fixture = fixture.setup_fixture
 cleanup_fixture = fixture.cleanup_fixture
 list_required_fixtures = fixture.list_required_fixtures
 SharedFixture = fixture.SharedFixture
+
+TobikoException = exceptions.TobikoException
+FailureException = exceptions.FailureException
diff --git a/tobiko/common/exceptions.py b/tobiko/common/exceptions.py
index 37b187856..ee1e7ced3 100644
--- a/tobiko/common/exceptions.py
+++ b/tobiko/common/exceptions.py
@@ -13,6 +13,8 @@
 #    under the License.
 from __future__ import absolute_import
 
+import testtools
+
 
 class TobikoException(Exception):
     """Base Tobiko Exception.
@@ -20,23 +22,27 @@ class TobikoException(Exception):
     To use this class, inherit from it and define a 'message' property.
     """
 
-    message = "An unknown exception occurred."
+    message = None
 
     def __init__(self, **properties):
         super(TobikoException, self).__init__()
         self._properties = properties
         message = self.message  # pylint: disable=exception-message-attribute
-        if properties:
-            message = message % properties
-        self._message = message
+        if message:
+            if properties:
+                message = message % properties
+        self._message = message or "unknown reason"
 
     def __str__(self):
         return self._message
 
-    def __getattr(self, name):
+    def __getattr__(self, name):
         try:
             return self._properties[name]
         except KeyError:
-            pass
-        msg = ("'{!r}' object has no attribute {!r}").format(self, name)
-        raise AttributeError(msg)
+            msg = ("{!r} object has no attribute {!r}").format(self, name)
+            raise AttributeError(msg)
+
+
+class FailureException(TobikoException, testtools.TestCase.failureException):
+    pass
diff --git a/tobiko/openstack/heat/_stack.py b/tobiko/openstack/heat/_stack.py
index d079ec7e1..5a1202853 100644
--- a/tobiko/openstack/heat/_stack.py
+++ b/tobiko/openstack/heat/_stack.py
@@ -20,7 +20,6 @@ from heatclient import exc
 from oslo_log import log
 
 import tobiko
-from tobiko.common import exceptions
 from tobiko.openstack.heat import _client
 from tobiko.openstack.heat import _template
 
@@ -245,15 +244,15 @@ def check_stack_status(stack, expected):
                           status_reason=stack.stack_status_reason)
 
 
-class InvalidHeatStackOutputKey(exceptions.TobikoException):
-    message = "Output key %(key)r not found in stack %(name)."
+class InvalidHeatStackOutputKey(tobiko.TobikoException):
+    message = "Output key %(key)r not found in stack %(name)r."
 
 
-class HeatStackNotFound(exceptions.TobikoException):
+class HeatStackNotFound(tobiko.TobikoException):
     message = "Stack %(name)r not found"
 
 
-class InvalidHeatStackStatus(exceptions.TobikoException):
+class InvalidHeatStackStatus(tobiko.TobikoException):
     message = ("Stack %(name)r status %(observed)r not in %(expected)r.\n"
                "%(status_reason)s")
 
diff --git a/tobiko/openstack/keystone/_credentials.py b/tobiko/openstack/keystone/_credentials.py
index ef5926a30..7d68c0154 100644
--- a/tobiko/openstack/keystone/_credentials.py
+++ b/tobiko/openstack/keystone/_credentials.py
@@ -18,7 +18,6 @@ import collections
 from oslo_log import log
 
 import tobiko
-from tobiko.common import exceptions
 
 
 LOG = log.getLogger(__name__)
@@ -74,7 +73,7 @@ def keystone_credentials(api_version=None, auth_url=None,
                project_domain_name=project_domain_name)
 
 
-class InvalidKeystoneCredentials(exceptions.TobikoException):
+class InvalidKeystoneCredentials(tobiko.TobikoException):
     message = "Invalid Keystone credentials (%(credentials)r): %(reason)s."