Check image after unshelve

During the shelve, a snapshot image is created
When unshelve is done, that created image
should be deleted.

A check is to ensure that there is no image
left after unshelve

Change-Id: Ia4cc0c153fee6bf6e010f8f02c21f8aeba45d7d9
diff --git a/tempest/api/compute/servers/test_server_actions.py b/tempest/api/compute/servers/test_server_actions.py
index 76b9c44..6f072b2 100644
--- a/tempest/api/compute/servers/test_server_actions.py
+++ b/tempest/api/compute/servers/test_server_actions.py
@@ -531,6 +531,10 @@
         self.client.unshelve_server(self.server_id)
         waiters.wait_for_server_status(self.client, self.server_id, 'ACTIVE')
 
+        images = self.compute_images_client.list_images(**params)['images']
+        msg = ('After unshelve, shelved image is not deleted.')
+        self.assertEmpty(images, msg)
+
     @decorators.idempotent_id('af8eafd4-38a7-4a4b-bdbc-75145a580560')
     def test_stop_start_server(self):
         self.client.stop_server(self.server_id)