PowerVM snapshot cleanup

This patch cleans up some nits left after the merge of [1].
- Uses mock_open() in test_stream_blockdev_to_glance
- Removes errant quote in InstanceDiskToMgmt() header
- Fixes method header for generate_snapshot_metadata()

[1] https://review.openstack.org/#/c/543023/

Change-Id: Iba75282db968f74ac2e4474c872ba59f9cd77652

nova/tests/unit/virt/powervm/test_image.py

@@ -21,25 +21,20 @@ from nova import test
 
 from nova.virt.powervm import image
 
-if six.PY2:
-    _BUILTIN = '__builtin__'
-else:
-    _BUILTIN = 'builtins'
-
 
 class TestImage(test.TestCase):
 
     @mock.patch('nova.utils.temporary_chown', autospec=True)
-    @mock.patch(_BUILTIN + '.open', autospec=True)
     @mock.patch('nova.image.api.API', autospec=True)
-    def test_stream_blockdev_to_glance(self, mock_api, mock_open, mock_chown):
-        mock_open.return_value.__enter__.return_value = 'mock_stream'
-        image.stream_blockdev_to_glance('context', mock_api, 'image_id',
-                                        'metadata', '/dev/disk')
+    def test_stream_blockdev_to_glance(self, mock_api, mock_chown):
+        mock_open = mock.mock_open()
+        with mock.patch.object(six.moves.builtins, 'open', new=mock_open):
+            image.stream_blockdev_to_glance('context', mock_api, 'image_id',
+                                            'metadata', '/dev/disk')
         mock_chown.assert_called_with('/dev/disk')
         mock_open.assert_called_with('/dev/disk', 'rb')
         mock_api.update.assert_called_with('context', 'image_id', 'metadata',
-                                           'mock_stream')
+                                           mock_open.return_value)
 
     @mock.patch('nova.image.api.API', autospec=True)
     def test_generate_snapshot_metadata(self, mock_api):

nova/virt/powervm/image.py

@@ -43,9 +43,11 @@ def generate_snapshot_metadata(context, image_api, image_id, instance):
     :param image_api: Handle to the glance image API.
     :param image_id: UUID of the prepared glance image.
     :param instance: The Nova instance whose disk is to be snapshotted.
-    :return: A dict of metadata suitable for image_api.upload.
+    :return: A dict of metadata suitable for image_api.update.
     """
     image = image_api.get(context, image_id)
+
+    # TODO(esberglu): Update this to v2 metadata
     metadata = {
         'name': image['name'],
         'is_public': False,

nova/virt/powervm/tasks/storage.py

@@ -212,7 +212,7 @@ class DeleteVOpt(task.Task):
 
 class InstanceDiskToMgmt(task.Task):
 
-    """The task to connect an instance's disk to the management partition."
+    """The task to connect an instance's disk to the management partition.
 
     This task will connect the instance's disk to the management partition and
     discover it. We do these two pieces together because their reversion