### Question:
BrokerInterceptor implements Interceptor { @Override public void notifyClientDisconnected(final String clientID, final String username) { for (final InterceptHandler handler : this.handlers.get(InterceptDisconnectMessage.class)) { if(LOG.isDebugEnabled()){ LOG.debug("Notifying MQTT client disconnection to interceptor. CId={}, username={}, interceptorId={}", clientID, username, handler.getID()); } executor.execute(new Runnable() { @Override public void run() { handler.onDisconnect(new InterceptDisconnectMessage(clientID, 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 MoquetteMessage 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 testNotifyClientDisconnected() throws Exception { interceptor.notifyClientDisconnected("cli1234", "cli1234"); interval(); assertEquals(50, n.get()); }