Verify list extensions attributes of V2/V3 APIs

This patch adds the JSON schema for Nova V2/V3 list extensions APIs
includes the attributes to block the backward incompatibility change
in the future.

The response body of v2 is the below:
{
    "extensions": [
        {
            "updated": "2011-06-09T00:00:00+00:00",
            "name": "Multinic",
            "links": [],
            "namespace": "http://xxx.xxx.xxx/xxx/xxx",
            "alias": "NMN",
            "description": "Multiple network support."
        }
    ]
}

The response body of v3 is the below:
{
    "extensions": [
        {
            "name": "Multinic",
            "alias": "NMN",
            "description": "Multiple network support.",
            "version": 1
        }
    ]
}

Partially implements blueprint nova-api-attribute-test

Change-Id: I0597a7b0d0732b00b77e4a6f0806391054470a6b
diff --git a/tempest/api_schema/compute/v2/extensions.py b/tempest/api_schema/compute/v2/extensions.py
new file mode 100644
index 0000000..570cd03
--- /dev/null
+++ b/tempest/api_schema/compute/v2/extensions.py
@@ -0,0 +1,45 @@
+# Copyright 2014 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.
+
+list_extensions = {
+    'status_code': [200],
+    'response_body': {
+        'type': 'object',
+        'properties': {
+            'extensions': {
+                'type': 'array',
+                'items': {
+                    'type': 'object',
+                    'properties': {
+                        'updated': {
+                            'type': 'string',
+                            'format': 'data-time'
+                        },
+                        'name': {'type': 'string'},
+                        'links': {'type': 'array'},
+                        'namespace': {
+                            'type': 'string',
+                            'format': 'uri'
+                        },
+                        'alias': {'type': 'string'},
+                        'description': {'type': 'string'}
+                    },
+                    'required': ['updated', 'name', 'links', 'namespace',
+                                 'alias', 'description']
+                }
+            }
+        },
+        'required': ['extensions']
+    }
+}
diff --git a/tempest/api_schema/compute/v3/extensions.py b/tempest/api_schema/compute/v3/extensions.py
new file mode 100644
index 0000000..ceb0ce2
--- /dev/null
+++ b/tempest/api_schema/compute/v3/extensions.py
@@ -0,0 +1,36 @@
+# Copyright 2014 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.
+
+list_extensions = {
+    'status_code': [200],
+    'response_body': {
+        'type': 'object',
+        'properties': {
+            'extensions': {
+                'type': 'array',
+                'items': {
+                    'type': 'object',
+                    'properties': {
+                        'name': {'type': 'string'},
+                        'alias': {'type': 'string'},
+                        'description': {'type': 'string'},
+                        'version': {'type': 'integer'}
+                    },
+                    'required': ['name', 'alias', 'description', 'version']
+                }
+            }
+        },
+        'required': ['extensions']
+    }
+}
diff --git a/tempest/services/compute/json/extensions_client.py b/tempest/services/compute/json/extensions_client.py
index 5ad8b98..ed2b14d 100644
--- a/tempest/services/compute/json/extensions_client.py
+++ b/tempest/services/compute/json/extensions_client.py
@@ -15,6 +15,7 @@
 
 import json
 
+from tempest.api_schema.compute.v2 import extensions as schema
 from tempest.common import rest_client
 from tempest import config
 
@@ -31,6 +32,7 @@
         url = 'extensions'
         resp, body = self.get(url)
         body = json.loads(body)
+        self.validate_response(schema.list_extensions, resp, body)
         return resp, body['extensions']
 
     def is_enabled(self, extension):
diff --git a/tempest/services/compute/v3/json/extensions_client.py b/tempest/services/compute/v3/json/extensions_client.py
index 46f17a4..13292db 100644
--- a/tempest/services/compute/v3/json/extensions_client.py
+++ b/tempest/services/compute/v3/json/extensions_client.py
@@ -15,6 +15,7 @@
 
 import json
 
+from tempest.api_schema.compute.v3 import extensions as schema
 from tempest.common import rest_client
 from tempest import config
 
@@ -31,6 +32,7 @@
         url = 'extensions'
         resp, body = self.get(url)
         body = json.loads(body)
+        self.validate_response(schema.list_extensions, resp, body)
         return resp, body['extensions']
 
     def is_enabled(self, extension):