final HelixDataAccessor accessor =
new ZKHelixDataAccessor(clusterName, _baseAccessor);
final PropertyKey.Builder keyBuilder = accessor.keyBuilder();
LiveInstance leader = accessor.getProperty(keyBuilder.controllerLeader());
Assert.assertNotNull(leader);
Assert.assertEquals(leader.getInstanceName(), controllerId.stringify());
// remove leader znode externally
accessor.removeProperty(keyBuilder.controllerLeader());
// verify leader is re-elected