Add "list Glance API versions" test

Many projects provides multiple API versions and the version
information is very important for users, because users can know
what features are available on clouds. However, Tempest didn't
test the Clance API versions in long-term. So this patch adds
the corresponding test.

Change-Id: Ib85819fb71f0b12b64351b307d83a3beb77d7fad
diff --git a/tempest/api/image/v2/test_versions.py b/tempest/api/image/v2/test_versions.py
new file mode 100644
index 0000000..24f104c
--- /dev/null
+++ b/tempest/api/image/v2/test_versions.py
@@ -0,0 +1,30 @@
+# Copyright 2017 NEC Corporation.  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.
+
+from tempest.api.image import base
+from tempest.lib import decorators
+from tempest import test
+
+
+class VersionsTest(base.BaseV2ImageTest):
+
+    @decorators.idempotent_id('659ea30a-a17c-4317-832c-0f68ed23c31d')
+    @test.attr(type='smoke')
+    def test_list_versions(self):
+        versions = self.versions_client.list_versions()['versions']
+        expected_resources = ('id', 'links', 'status')
+
+        for version in versions:
+            for res in expected_resources:
+                self.assertIn(res, version)