From 852bd45c94df4a5c5ccb1e42077ec4f2d1a57272 Mon Sep 17 00:00:00 2001
From: Mark Hamzy <hamzy@us.ibm.com>
Date: Mon, 5 Mar 2018 15:18:31 -0600
Subject: [PATCH] Fix formatting of ImportError

Fix formatting of ImportError when using a driver not found in the list
of token providers.

Change-Id: I0ac8ac199aeebd20960ad0654461f1f81c4d7da0
Closes-bug: 1753584
---
 keystone/common/manager.py                         |  2 +-
 keystone/tests/unit/token/test_common.py           | 14 ++++++++++++++
 .../notes/bug-1753584-e052bc7805f001b4.yaml        |  6 ++++++
 3 files changed, 21 insertions(+), 1 deletion(-)
 create mode 100644 releasenotes/notes/bug-1753584-e052bc7805f001b4.yaml

diff --git a/keystone/common/manager.py b/keystone/common/manager.py
index 4a60e8566f..9934fd8af9 100644
--- a/keystone/common/manager.py
+++ b/keystone/common/manager.py
@@ -78,7 +78,7 @@ def load_driver(namespace, driver_name, *args):
         return driver_manager.driver
     except stevedore.exception.NoMatches:
         msg = (_('Unable to find %(name)r driver in %(namespace)r.'))
-        raise ImportError(msg, {'name': driver_name, 'namespace': namespace})
+        raise ImportError(msg % {'name': driver_name, 'namespace': namespace})
 
 
 class _TraceMeta(type):
diff --git a/keystone/tests/unit/token/test_common.py b/keystone/tests/unit/token/test_common.py
index 4f028c6cd0..ac835b9dcc 100644
--- a/keystone/tests/unit/token/test_common.py
+++ b/keystone/tests/unit/token/test_common.py
@@ -10,9 +10,12 @@
 # License for the specific language governing permissions and limitations
 # under the License.
 
+import uuid
+
 from six.moves import urllib
 
 from keystone.tests import unit
+from keystone.token import provider
 from keystone.token.providers import common
 
 
@@ -20,3 +23,14 @@ class TestTokenProvidersCommon(unit.TestCase):
     def test_strings_are_url_safe(self):
         s = common.random_urlsafe_str()
         self.assertEqual(s, urllib.parse.quote_plus(s))
+
+    def test_unsupported_provider_raises_import_error(self):
+        namespace = "keystone.token.provider"
+        # Generate a random name
+        driver = uuid.uuid4().hex
+        self.config_fixture.config(group='token', provider=driver)
+        msg = "Unable to find '%(driver)s' driver in '%(namespace)s'." % {
+            'namespace': namespace, 'driver': driver
+        }
+
+        self.assertRaisesRegex(ImportError, msg, provider.Manager)
diff --git a/releasenotes/notes/bug-1753584-e052bc7805f001b4.yaml b/releasenotes/notes/bug-1753584-e052bc7805f001b4.yaml
new file mode 100644
index 0000000000..c431f980e5
--- /dev/null
+++ b/releasenotes/notes/bug-1753584-e052bc7805f001b4.yaml
@@ -0,0 +1,6 @@
+---
+fixes:
+  - |
+    [`bug 1753584 <https://bugs.launchpad.net/keystone/+bug/1753584>`_]
+    Fix formatting of ImportError when using a driver not found in the list
+    of token providers.