int serviceClass, boolean noChanged) throws IOException{
Client client = new Client(LongWritable.class, conf);
client.call(new LongWritable(RANDOM.nextLong()),
addr, null, null, MIN_SLEEP_TIME, serviceClass, conf);
Connection connection = server.getConnections().get(0);
int serviceClass2 = connection.getServiceClass();
assertFalse(noChanged ^ serviceClass == serviceClass2);
client.stop();
}