add negative test cases for create snapshots:

- test_create_snapshot_with_nonexistent_volume_id
- test_create_snapshot_without_passing_volume_id

Change-Id: I3e105b51a96566e714adc655394f1ff9b2748cb5
diff --git a/tempest/api/volume/test_volumes_snapshots_negative.py b/tempest/api/volume/test_volumes_snapshots_negative.py
new file mode 100644
index 0000000..04a4774
--- /dev/null
+++ b/tempest/api/volume/test_volumes_snapshots_negative.py
@@ -0,0 +1,44 @@
+# vim: tabstop=4 shiftwidth=4 softtabstop=4
+
+#    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.
+
+import uuid
+
+from tempest.api.volume import base
+from tempest.common.utils import data_utils
+from tempest import exceptions
+from tempest.test import attr
+
+
+class VolumesSnapshotNegativeTest(base.BaseVolumeTest):
+    _interface = "json"
+
+    @attr(type=['negative', 'gate'])
+    def test_create_snapshot_with_nonexistent_volume_id(self):
+        # Create a snapshot with nonexistent volume id
+        s_name = data_utils.rand_name('snap')
+        self.assertRaises(exceptions.NotFound,
+                          self.snapshots_client.create_snapshot,
+                          str(uuid.uuid4()), display_name=s_name)
+
+    @attr(type=['negative', 'gate'])
+    def test_create_snapshot_without_passing_volume_id(self):
+        # Create a snapshot without passing volume id
+        s_name = data_utils.rand_name('snap')
+        self.assertRaises(exceptions.NotFound,
+                          self.snapshots_client.create_snapshot,
+                          None, display_name=s_name)
+
+
+class VolumesSnapshotNegativeTestXML(VolumesSnapshotNegativeTest):
+    _interface = "xml"