@Override
    public RequestStatus updateResources(Request request, Predicate predicate)
        throws SystemException, UnsupportedPropertyException, NoSuchResourceException, NoSuchParentResourceException {
      return new RequestStatusImpl(null);
    }
A test observer that records the last event.
ambari-server/src/test/java/org/apache/ambari/server/controller/internal/AbstractResourceProviderTest.java