Fix wrong usage of rbd.list_snaps return value

the return value of rbd.list_snaps is a generator with dict.

Co-Authored-By: Ivan Kolodyazhny <e0ne@e0ne.info>
Change-Id: Id3576a52e253ed242685999e96d638e98ce605bf
Closes-Bug: #1681895
(cherry picked from commit 3e2a593ae9)

cinder/backup/drivers/ceph.py

@@ -585,7 +585,7 @@ class CephBackupDriver(driver.BackupDriver):
             return False
 
         for snap in snaps:
-            if snap.name == snap_name:
+            if snap['name'] == snap_name:
                 return True
 
         return False

cinder/tests/unit/backup/drivers/test_backup_ceph.py

@@ -19,6 +19,7 @@ import os
 import tempfile
 import uuid
 
+import ddt
 import mock
 from os_brick.initiator import linuxrbd
 from oslo_concurrency import processutils
@@ -98,6 +99,7 @@ def common_mocks(f):
     return _common_inner_inner1
 
 
+@ddt.ddt
 class BackupCephTestCase(test.TestCase):
     """Test case for ceph backup driver."""
 
@@ -1105,6 +1107,19 @@ class BackupCephTestCase(test.TestCase):
 
         self.assertTrue(self.mock_rados.Object.return_value.read.called)
 
+    @ddt.data((None, False),
+              ([{'name': 'test'}], False),
+              ([{'name': 'test'}, {'name': 'fake'}], True))
+    @ddt.unpack
+    @common_mocks
+    def test__snap_exists(self, snapshots, snap_exist):
+        client = mock.Mock()
+        with mock.patch.object(self.service.rbd.Image(),
+                               'list_snaps') as snaps:
+            snaps.return_value = snapshots
+            exist = self.service._snap_exists(None, 'fake', client)
+            self.assertEqual(snap_exist, exist)
+
 
 def common_meta_backup_mocks(f):
     """Decorator to set mocks common to all metadata backup tests.