@Test
public void normalShutdown() throws InterruptedException {
Logger logger = LoggerFactory.getLogger("test");
MockLog4jAppender appender = new MockLog4jAppender();
appender.addToLogger("test");
//time not enough to shutdown,write error log.
appender.clearLogs();
ExecutorService pool = Executors.newSingleThreadExecutor();
Runnable task = new Task(logger, 1000, 0);