Move _get_locations to module level plus tests

Moves the nova.image.glance.GlanceImageService._get_locations object
method into module level scope (the self argument was unused) and
adds full unit tests for the nova.image.glance._get_location() function.

Change-Id: Ib386330b70abe1e0353f1fafa3e68bc3e7a2d1b1
Partial-bug: #1293938

nova/image/glance.py

@@ -277,25 +277,6 @@ class GlanceImageService(object):
         base_image_meta = _translate_from_glance(image)
         return base_image_meta
 
-    def _get_locations(self, context, image_id):
-        """Returns the direct url representing the backend storage location,
-        or None if this attribute is not shown by Glance.
-        """
-        try:
-            client = GlanceClientWrapper()
-            image_meta = client.call(context, 2, 'get', image_id)
-        except Exception:
-            _reraise_translated_image_exception(image_id)
-
-        if not _is_image_available(context, image_meta):
-            raise exception.ImageNotFound(image_id=image_id)
-
-        locations = getattr(image_meta, 'locations', [])
-        du = getattr(image_meta, 'direct_url', None)
-        if du:
-            locations.append({'url': du, 'metadata': {}})
-        return locations
-
     def _get_transfer_module(self, scheme):
         try:
             return self._download_handlers[scheme]
@@ -309,7 +290,7 @@ class GlanceImageService(object):
     def download(self, context, image_id, data=None, dst_path=None):
         """Calls out to Glance for data and writes data."""
         if CONF.allowed_direct_url_schemes and dst_path is not None:
-            locations = self._get_locations(context, image_id)
+            locations = _get_locations(self._client, context, image_id)
             for entry in locations:
                 loc_url = entry['url']
                 loc_meta = entry['metadata']
@@ -395,6 +376,25 @@ class GlanceImageService(object):
         return True
 
 
+def _get_locations(client, context, image_id):
+    """Returns the direct url representing the backend storage location,
+    or None if this attribute is not shown by Glance.
+    """
+    try:
+        image_meta = client.call(context, 2, 'get', image_id)
+    except Exception:
+        _reraise_translated_image_exception(image_id)
+
+    if not _is_image_available(context, image_meta):
+        raise exception.ImageNotFound(image_id=image_id)
+
+    locations = getattr(image_meta, 'locations', [])
+    du = getattr(image_meta, 'direct_url', None)
+    if du:
+        locations.append({'url': du, 'metadata': {}})
+    return locations
+
+
 def _extract_query_params(params):
     _params = {}
     accepted_params = ('filters', 'marker', 'limit',

nova/tests/image/test_glance.py

@@ -466,6 +466,68 @@ def _create_failing_glance_client(info):
     return MyGlanceStubClient()
 
 
+class TestGetLocations(test.NoDBTestCase):
+    """Tests the internal _get_locations function."""
+
+    class ImageSpecV2(object):
+        visibility = None
+        properties = None
+        locations = None
+        direct_url = None
+
+    @mock.patch('nova.image.glance._is_image_available')
+    def test_success_has_locations(self, avail_mock):
+        avail_mock.return_value = True
+        locations = [
+            mock.sentinel.loc1
+        ]
+        image_meta = mock.MagicMock(locations=locations,
+                                    spec=TestGetLocations.ImageSpecV2)
+
+        client_mock = mock.MagicMock()
+        client_mock.call.return_value = image_meta
+        locs = glance._get_locations(client_mock, mock.sentinel.ctx,
+                                     mock.sentinel.image_id)
+        client_mock.call.assert_called_once_with(mock.sentinel.ctx,
+                                                 2, 'get',
+                                                 mock.sentinel.image_id)
+        self.assertEqual(locations, locs)
+        avail_mock.assert_called_once_with(mock.sentinel.ctx, image_meta)
+
+    @mock.patch('nova.image.glance._is_image_available')
+    def test_success_direct_uri_added_to_locations(self, avail_mock):
+        avail_mock.return_value = True
+        locations = [
+            mock.sentinel.loc1
+        ]
+        image_meta = mock.MagicMock(locations=locations,
+                                    spec=TestGetLocations.ImageSpecV2,
+                                    direct_uri=mock.sentinel.duri)
+
+        client_mock = mock.MagicMock()
+        client_mock.call.return_value = image_meta
+        locs = glance._get_locations(client_mock, mock.sentinel.ctx,
+                                     mock.sentinel.image_id)
+        client_mock.call.assert_called_once_with(mock.sentinel.ctx,
+                                                 2, 'get',
+                                                 mock.sentinel.image_id)
+        expected = locations
+        expected.append({"url": mock.sentinel.duri, "metadata": {}})
+        self.assertEqual(expected, locs)
+
+    @mock.patch('nova.image.glance._reraise_translated_image_exception')
+    @mock.patch('nova.image.glance._is_image_available')
+    def test_get_locations_not_found(self, avail_mock, reraise_mock):
+        raised = exception.ImageNotFound(image_id=123)
+        reraise_mock.side_effect = raised
+
+        client_mock = mock.MagicMock()
+        client_mock.call.side_effect = glanceclient.exc.NotFound
+        self.assertRaises(exception.ImageNotFound, glance._get_locations,
+                          client_mock, mock.sentinel.ctx,
+                          mock.sentinel.image_id)
+
+
 class TestIsImageAvailable(test.NoDBTestCase):
     """Tests the internal _is_image_available function."""