### Question:
BrokerInterceptor implements Interceptor { @Override public void notifyTopicSubscribed(final Subscription sub, final String username) { for (final InterceptHandler handler : this.handlers.get(InterceptSubscribeMessage.class)) { LOG.debug("Notifying MQTT SUBSCRIBE message to interceptor. CId={}, topicFilter={}, interceptorId={}", sub.getClientId(), sub.getTopicFilter(), handler.getID()); executor.execute(() -> handler.onSubscribe(new InterceptSubscribeMessage(sub, username))); } } private  BrokerInterceptor(int poolSize, List<InterceptHandler> handlers);   BrokerInterceptor(List<InterceptHandler> handlers);   BrokerInterceptor(IConfig props, List<InterceptHandler> handlers); @Override void notifyClientConnected(final MqttConnectMessage msg); @Override void notifyClientDisconnected(final String clientID, final String username); @Override void notifyClientConnectionLost(final String clientID, final String username); @Override void notifyTopicPublished(final MqttPublishMessage msg, final String clientID, final String username); @Override void notifyTopicSubscribed(final Subscription sub, final String username); @Override void notifyTopicUnsubscribed(final String topic, final String clientID, final String username); @Override void notifyMessageAcknowledged(final InterceptAcknowledgedMessage msg); @Override void addInterceptHandler(InterceptHandler interceptHandler); @Override void removeInterceptHandler(InterceptHandler interceptHandler);  }### Answer:
@Test public void testNotifyTopicSubscribed() throws Exception { interceptor.notifyTopicSubscribed(new Subscription("cli1", new Topic("o2"), MqttQoS.AT_MOST_ONCE), "cli1234"); interval(); assertEquals(70, n.get()); }