@Override
    public void configure(Binder binder) {
      binder.bind(TopologyManager.class).toInstance(createNiceMock(TopologyManager.class));
    }
Tests that {@link HostRegisteredEvent} properly updates the
{@link Clusters} in-memory mapping of hostIds to hosts.

@throws AmbariException
ambari-server/src/test/java/org/apache/ambari/server/state/cluster/ClustersTest.java