### Question:
ProducerConnectionSubCommand implements SubCommand { @Override public void execute(CommandLine commandLine, Options options, RPCHook rpcHook) { DefaultMQAdminExt defaultMQAdminExt = new DefaultMQAdminExt(rpcHook); defaultMQAdminExt.setInstanceName(Long.toString(System.currentTimeMillis())); try { defaultMQAdminExt.start(); String group = commandLine.getOptionValue('g').trim(); String topic = commandLine.getOptionValue('t').trim(); ProducerConnection pc = defaultMQAdminExt.examineProducerConnectionInfo(group, topic); int i = 1; for (Connection conn : pc.getConnectionSet()) { System.out.printf("%04d %-32s %-22s %-8s %s%n", i++, conn.getClientId(), conn.getClientAddr(), conn.getLanguage(), MQVersion.getVersionDesc(conn.getVersion()) ); } } catch (Exception e) { e.printStackTrace(); } finally { defaultMQAdminExt.shutdown(); } }  @Override String commandName(); @Override String commandDesc(); @Override Options buildCommandlineOptions(Options options); @Override void execute(CommandLine commandLine, Options options, RPCHook rpcHook);  }### Answer:
@Test public void testExecute() { ProducerConnectionSubCommand cmd = new ProducerConnectionSubCommand(); Options options = ServerUtil.buildCommandlineOptions(new Options()); String[] subargs = new String[] {"-g default-producer-group", "-t unit-test"}; final CommandLine commandLine = ServerUtil.parseCmdLine("mqadmin " + cmd.commandName(), subargs, cmd.buildCommandlineOptions(options), new PosixParser()); cmd.execute(commandLine, options, null); }