Add more descriptive assertion message for test_create_backup

In order to fingerprint the failure for gate race bug 1267326 in
elastic-recheck, the assertion message needs to be specific to the test
case that's failing. We have to do something like this until we have
multi-line query support in elastic-recheck.

Also makes the backup names more specific.

Related-Bug: #1267326

Change-Id: I4cf4a3409eedf64f928ae7b0ff4a660c116b89bc
diff --git a/tempest/api/compute/servers/test_server_actions.py b/tempest/api/compute/servers/test_server_actions.py
index 582faf8..6a0a195 100644
--- a/tempest/api/compute/servers/test_server_actions.py
+++ b/tempest/api/compute/servers/test_server_actions.py
@@ -230,7 +230,7 @@
     def test_create_backup(self):
         # Positive test:create backup successfully and rotate backups correctly
         # create the first and the second backup
-        backup1 = data_utils.rand_name('backup')
+        backup1 = data_utils.rand_name('backup-1')
         resp, _ = self.servers_client.create_backup(self.server_id,
                                                     'daily',
                                                     2,
@@ -247,7 +247,7 @@
         self.assertEqual(202, resp.status)
         self.os.image_client.wait_for_image_status(image1_id, 'active')
 
-        backup2 = data_utils.rand_name('backup')
+        backup2 = data_utils.rand_name('backup-2')
         self.servers_client.wait_for_server_status(self.server_id, 'ACTIVE')
         resp, _ = self.servers_client.create_backup(self.server_id,
                                                     'daily',
@@ -275,7 +275,7 @@
 
         # create the third one, due to the rotation is 2,
         # the first one will be deleted
-        backup3 = data_utils.rand_name('backup')
+        backup3 = data_utils.rand_name('backup-3')
         self.servers_client.wait_for_server_status(self.server_id, 'ACTIVE')
         resp, _ = self.servers_client.create_backup(self.server_id,
                                                     'daily',
@@ -293,7 +293,11 @@
             sort_key='created_at',
             sort_dir='asc')
         self.assertEqual(200, resp.status)
-        self.assertEqual(2, len(image_list))
+        self.assertEqual(2, len(image_list),
+                         'Unexpected number of images for '
+                         'v2:test_create_backup; was the oldest backup not '
+                         'yet deleted? Image list: %s' %
+                         [image['name'] for image in image_list])
         self.assertEqual((backup2, backup3),
                          (image_list[0]['name'], image_list[1]['name']))
 
diff --git a/tempest/api/compute/v3/servers/test_server_actions.py b/tempest/api/compute/v3/servers/test_server_actions.py
index eb7bc94..32b0433 100644
--- a/tempest/api/compute/v3/servers/test_server_actions.py
+++ b/tempest/api/compute/v3/servers/test_server_actions.py
@@ -225,7 +225,7 @@
     def test_create_backup(self):
         # Positive test:create backup successfully and rotate backups correctly
         # create the first and the second backup
-        backup1 = data_utils.rand_name('backup')
+        backup1 = data_utils.rand_name('backup-1')
         resp, _ = self.servers_client.create_backup(self.server_id,
                                                     'daily',
                                                     2,
@@ -242,7 +242,7 @@
         self.assertEqual(202, resp.status)
         self.images_client.wait_for_image_status(image1_id, 'active')
 
-        backup2 = data_utils.rand_name('backup')
+        backup2 = data_utils.rand_name('backup-2')
         self.servers_client.wait_for_server_status(self.server_id, 'ACTIVE')
         resp, _ = self.servers_client.create_backup(self.server_id,
                                                     'daily',
@@ -270,7 +270,7 @@
 
         # create the third one, due to the rotation is 2,
         # the first one will be deleted
-        backup3 = data_utils.rand_name('backup')
+        backup3 = data_utils.rand_name('backup-3')
         self.servers_client.wait_for_server_status(self.server_id, 'ACTIVE')
         resp, _ = self.servers_client.create_backup(self.server_id,
                                                     'daily',
@@ -287,7 +287,11 @@
             sort_key='created_at',
             sort_dir='asc')
         self.assertEqual(200, resp.status)
-        self.assertEqual(2, len(image_list))
+        self.assertEqual(2, len(image_list),
+                         'Unexpected number of images for '
+                         'v3:test_create_backup; was the oldest backup not '
+                         'yet deleted? Image list: %s' %
+                         [image['name'] for image in image_list])
         self.assertEqual((backup2, backup3),
                          (image_list[0]['name'], image_list[1]['name']))