Verify the response attributes of 'list_hosts'

This patch verifies the response attributes of list_hosts.
The response body of v2 and v3 API are in the same format:

"hosts": [
    {
        "host_name": "b6e4adbc193d428ea923899d07fb001e",
        "service": "conductor",
        "zone": "internal"
    }
]

Partially implements blueprint nova-api-attribute-test

Change-Id: Ia26d14e6fcec0e8f76224669ebde57ff8840605c
diff --git a/tempest/api_schema/compute/hosts.py b/tempest/api_schema/compute/hosts.py
new file mode 100644
index 0000000..b9a3db9
--- /dev/null
+++ b/tempest/api_schema/compute/hosts.py
@@ -0,0 +1,35 @@
+# 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_hosts = {
+    'status_code': [200],
+    'response_body': {
+        'type': 'object',
+        'properties': {
+            'hosts': {
+                'type': 'array',
+                'items': {
+                    'type': 'object',
+                    'properties': {
+                        'host_name': {'type': 'string'},
+                        'service': {'type': 'string'},
+                        'zone': {'type': 'string'}
+                    },
+                    'required': ['host_name', 'service', 'zone']
+                }
+            }
+        },
+        'required': ['hosts']
+    }
+}
diff --git a/tempest/services/compute/json/hosts_client.py b/tempest/services/compute/json/hosts_client.py
index fb45997..0130f27 100644
--- a/tempest/services/compute/json/hosts_client.py
+++ b/tempest/services/compute/json/hosts_client.py
@@ -15,6 +15,7 @@
 import json
 import urllib
 
+from tempest.api_schema.compute import hosts as schema
 from tempest.common import rest_client
 from tempest import config
 
@@ -36,6 +37,7 @@
 
         resp, body = self.get(url)
         body = json.loads(body)
+        self.validate_response(schema.list_hosts, resp, body)
         return resp, body['hosts']
 
     def show_host_detail(self, hostname):
diff --git a/tempest/services/compute/v3/json/hosts_client.py b/tempest/services/compute/v3/json/hosts_client.py
index e27c7c6..bcb9d36 100644
--- a/tempest/services/compute/v3/json/hosts_client.py
+++ b/tempest/services/compute/v3/json/hosts_client.py
@@ -15,6 +15,7 @@
 import json
 import urllib
 
+from tempest.api_schema.compute import hosts as schema
 from tempest.common import rest_client
 from tempest import config
 
@@ -36,6 +37,7 @@
 
         resp, body = self.get(url)
         body = json.loads(body)
+        self.validate_response(schema.list_hosts, resp, body)
         return resp, body['hosts']
 
     def show_host_detail(self, hostname):