Check hypervisor statistics attributes of Nova API

This patch adds the JSON Schema for response of Nova V2 & V3
hypervisor statistics APIs ('os-hypervisors/statistics)
and validate the response with added JSON Schema to block
the backward incompatibility change in the future.

The response body of V2 & V3 hypervisor statistics APIs is same
& given below:

{
    "hypervisor_statistics": {
        "count": 1,
        "current_workload": 0,
        "disk_available_least": 0,
        "free_disk_gb": 1028,
        "free_ram_mb": 7680,
        "local_gb": 1028,
        "local_gb_used": 0,
        "memory_mb": 8192,
        "memory_mb_used": 512,
        "running_vms": 0,
        "vcpus": 1,
        "vcpus_used": 0
    }
}

Partially implements blueprint nova-api-attribute-test

Change-Id: I7cd1e81c722e0117b9f2fc98e9b2d2bf7eb5177c
diff --git a/tempest/api_schema/compute/hypervisors.py b/tempest/api_schema/compute/hypervisors.py
new file mode 100644
index 0000000..0cbafb3
--- /dev/null
+++ b/tempest/api_schema/compute/hypervisors.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.
+
+hypervisor_statistics = {
+    'status_code': [200],
+    'response_body': {
+        'type': 'object',
+        'properties': {
+            'hypervisor_statistics': {
+                'type': 'object',
+                'properties': {
+                    'count': {'type': 'integer'},
+                    'current_workload': {'type': 'integer'},
+                    'disk_available_least': {'type': 'integer'},
+                    'free_disk_gb': {'type': 'integer'},
+                    'free_ram_mb': {'type': 'integer'},
+                    'local_gb': {'type': 'integer'},
+                    'local_gb_used': {'type': 'integer'},
+                    'memory_mb': {'type': 'integer'},
+                    'memory_mb_used': {'type': 'integer'},
+                    'running_vms': {'type': 'integer'},
+                    'vcpus': {'type': 'integer'},
+                    'vcpus_used': {'type': 'integer'}
+                },
+                'required': ['count', 'current_workload',
+                             'disk_available_least', 'free_disk_gb',
+                             'free_ram_mb', 'local_gb', 'local_gb_used',
+                             'memory_mb', 'memory_mb_used', 'running_vms',
+                             'vcpus', 'vcpus_used']
+            }
+        },
+        'required': ['hypervisor_statistics']
+    }
+}
diff --git a/tempest/services/compute/json/hypervisor_client.py b/tempest/services/compute/json/hypervisor_client.py
index c6b13b0..be704e7 100644
--- a/tempest/services/compute/json/hypervisor_client.py
+++ b/tempest/services/compute/json/hypervisor_client.py
@@ -15,6 +15,7 @@
 
 import json
 
+from tempest.api_schema.compute import hypervisors as common_schema
 from tempest.common import rest_client
 from tempest import config
 
@@ -55,6 +56,7 @@
         """Get hypervisor statistics over all compute nodes."""
         resp, body = self.get('os-hypervisors/statistics')
         body = json.loads(body)
+        self.validate_response(common_schema.hypervisor_statistics, resp, body)
         return resp, body['hypervisor_statistics']
 
     def get_hypervisor_uptime(self, hyper_id):
diff --git a/tempest/services/compute/v3/json/hypervisor_client.py b/tempest/services/compute/v3/json/hypervisor_client.py
index 30e391f..54a6e17 100644
--- a/tempest/services/compute/v3/json/hypervisor_client.py
+++ b/tempest/services/compute/v3/json/hypervisor_client.py
@@ -15,6 +15,7 @@
 
 import json
 
+from tempest.api_schema.compute import hypervisors as common_schema
 from tempest.common import rest_client
 from tempest import config
 
@@ -55,6 +56,7 @@
         """Get hypervisor statistics over all compute nodes."""
         resp, body = self.get('os-hypervisors/statistics')
         body = json.loads(body)
+        self.validate_response(common_schema.hypervisor_statistics, resp, body)
         return resp, body['hypervisor_statistics']
 
     def get_hypervisor_uptime(self, hyper_id):