Add create image functional negative tests

The negative tests of create image API are not covered enough
in functional tests. We want to add the conflict tests of
when the create image API runs in the unexpected state
(e.g. not ACTIVE) of server.

Change-Id: I0c0b9e4d9ef1c5311113177dec46432f35b5ed63

nova/tests/functional/test_images.py

@@ -0,0 +1,60 @@
+#    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.
+
+from nova.tests.functional.api import client
+from nova.tests.functional import test_servers
+
+
+class ImagesTest(test_servers.ServersTestBase):
+
+    def test_create_images_negative_invalid_state(self):
+        # Create server
+        server = self._build_minimal_create_server_request()
+        created_server = self.api.post_server({"server": server})
+        server_id = created_server['id']
+        found_server = self._wait_for_state_change(created_server, 'BUILD')
+        self.assertEqual('ACTIVE', found_server['status'])
+
+        # Create image
+        name = 'Snapshot 1'
+        self.api.post_server_action(
+            server_id, {'createImage': {'name': name}})
+        self.assertEqual('ACTIVE', found_server['status'])
+        # Confirm that the image was created
+        images = self.api.get_images(detail=False)
+        image_map = {image['name']: image for image in images}
+        found_image = image_map.get(name)
+        self.assertTrue(found_image)
+
+        # Change server status from ACTIVE to SHELVED for negative test
+        self.flags(shelved_offload_time = -1)
+        self.api.post_server_action(server_id, {'shelve': {}})
+        found_server = self._wait_for_state_change(found_server, 'ACTIVE')
+        self.assertEqual('SHELVED', found_server['status'])
+
+        # Create image in SHELVED (not ACTIVE, etc.)
+        name = 'Snapshot 2'
+        ex = self.assertRaises(client.OpenStackApiException,
+                               self.api.post_server_action,
+                               server_id,
+                               {'createImage': {'name': name}})
+        self.assertEqual(409, ex.response.status_code)
+        self.assertEqual('SHELVED', found_server['status'])
+
+        # Confirm that the image was not created
+        images = self.api.get_images(detail=False)
+        image_map = {image['name']: image for image in images}
+        found_image = image_map.get(name)
+        self.assertFalse(found_image)
+
+        # Cleanup
+        self._delete_server(server_id)