Add update attached volume function to servers_client

os-volume_attachments API for update:
PUT /v2.1/{tenant_id}/servers/{server_id}/os-volume_attachments/{attachment_id}

tenant_id: The project ID (tenant ID) that the target server belongs to
server_id: The server ID to update the volume attachment
attachment_id: The volume attachment ID to update

Request body sample:
{
    "volumeAttachment": {
        "volumeId": "a26887c6-c47b-4654-abb5-dfadf7d3f805"
    }
}

volumeId: The volume ID to attach instead of the volume
          that has already been attached

This API does not return a response body.

Reference:
- Request body sample
  https://github.com/openstack/nova/blob/master/doc/api_samples/os-volumes/update-volume-req.json

- Fuctional test
  test_volume_attachment_update method in
  VolumeAttachmentsSample class
  https://github.com/openstack/nova/blob/master/nova/tests/functional/api_sample_tests/test_volumes.py

Change-Id: Ic0258e5688be6ede3316ab4310e9ca6ac0f51659
Implements: blueprint add-nova-swap-volume-tests

tempest_lib/api_schema/response/compute/v2_1/servers.py

@@ -547,3 +547,7 @@ server_actions_delete_password = {
 
 server_actions_confirm_resize = copy.deepcopy(
     server_actions_delete_password)
+
+update_attached_volume = {
+    'status_code': [202]
+}

tempest_lib/services/compute/servers_client.py

@@ -312,6 +312,15 @@ class ServersClient(rest_client.RestClient):
         self.validate_response(schema.attach_volume, resp, body)
         return rest_client.ResponseBody(resp, body)
 
+    def update_attached_volume(self, server_id, attachment_id, **kwargs):
+        """Swaps a volume attached to an instance for another volume"""
+        post_body = json.dumps({'volumeAttachment': kwargs})
+        resp, body = self.put('servers/%s/os-volume_attachments/%s' %
+                              (server_id, attachment_id),
+                              post_body)
+        self.validate_response(schema.update_attached_volume, resp, body)
+        return rest_client.ResponseBody(resp, body)
+
     def detach_volume(self, server_id, volume_id):  # noqa
         """Detaches a volume from a server instance."""
         resp, body = self.delete('servers/%s/os-volume_attachments/%s' %

tempest_lib/tests/services/compute/test_servers_client.py

@@ -564,6 +564,17 @@ class TestServersClient(base.BaseComputeServiceTest):
             server_id=self.server_id
             )
 
+    def test_update_attached_volume(self):
+        self.check_service_client_function(
+            self.client.update_attached_volume,
+            'tempest_lib.common.rest_client.RestClient.put',
+            {},
+            status=202,
+            server_id=self.server_id,
+            attachment_id='fake-attachment-id',
+            volumeId='fake-volume-id'
+            )
+
     def test_detach_volume_with_str_body(self):
         self._test_detach_volume_server()