Add test fixture for the JWS key repository

This commit introduces a fixture similar to what we use for Fernet
token keys. This will be set and used for JWS specific tests.

bp json-web-tokens

Change-Id: Iaf7dcba0c45ced72f1c2e442775592670bf941eb

keystone/tests/unit/ksfixtures/__init__.py

@@ -14,5 +14,6 @@
 from keystone.tests.unit.ksfixtures.auth_plugins import ConfigAuthPlugins  # noqa
 from keystone.tests.unit.ksfixtures.backendloader import BackendLoader  # noqa
 from keystone.tests.unit.ksfixtures.cache import Cache  # noqa
+from keystone.tests.unit.ksfixtures.jws_key_repository import JWSKeyRepository  # noqa
 from keystone.tests.unit.ksfixtures.key_repository import KeyRepository  # noqa
 from keystone.tests.unit.ksfixtures.policy import Policy  # noqa

keystone/tests/unit/ksfixtures/jws_key_repository.py

@@ -0,0 +1,51 @@
+# 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.
+
+import os
+
+import fixtures
+
+from keystone.common import jwt_utils
+from keystone.common import utils
+
+
+class JWSKeyRepository(fixtures.Fixture):
+    def __init__(self, config_fixture):
+        super(JWSKeyRepository, self).__init__()
+        self.config_fixture = config_fixture
+        self.key_group = 'jwt_tokens'
+
+    def setUp(self):
+        super(JWSKeyRepository, self).setUp()
+
+        # grab a couple of temporary directory file paths
+        private_key_directory = self.useFixture(fixtures.TempDir()).path
+        public_key_directory = self.useFixture(fixtures.TempDir()).path
+
+        # set config to use temporary paths
+        self.config_fixture.config(
+            group=self.key_group,
+            jws_private_key_repository=private_key_directory
+        )
+        self.config_fixture.config(
+            group=self.key_group,
+            jws_public_key_repository=public_key_directory
+        )
+
+        # create temporary repositories
+        utils.create_directory(private_key_directory)
+        utils.create_directory(public_key_directory)
+
+        # create an asymmetric key pair for token signing and validation
+        private_key_path = os.path.join(private_key_directory, 'private.pem')
+        public_key_path = os.path.join(public_key_directory, 'public.pem')
+        jwt_utils.create_jws_keypair(private_key_path, public_key_path)