Add notification sample test for aggregate.cache_images.start|end

This adds the functional notification sample test for the
aggregate.cache_images.start and aggregate.cache_images.end
versioned notifications.

I also added a comment to the docs builder code since it took
me a bit to figure out how to get the notification sample
linked into the docs, and for whatever reason figured that out
by looking through code rather than our nicely detailed docs
that already explain it.

Part of blueprint image-precache-support

Change-Id: I0869979a1b8a0966f0e7b49e5a5984f76d7d67cd

1 files changed, 4 insertions, 0 deletions

diff --git a/doc/ext/versioned_notifications.py b/doc/ext/versioned_notifications.py
index 7972b87277..09a7621c8a 100644
--- a/doc/ext/versioned_notifications.py
+++ b/doc/ext/versioned_notifications.py
@@ -61,6 +61,10 @@ jQuery(document).ready(function(){
                   pkgutil.iter_modules(nova.notifications.objects.__path__))))
 
     def _collect_notifications(self):
+        # If you do not see your notification sample showing up in the docs
+        # be sure that the sample filename matches what is registered on the
+        # versioned notification object class using the
+        # @base.notification_sample decorator.
         self._import_all_notification_packages()
         base.NovaObjectRegistry.register_notification_objects()
         notifications = {}