### Question:
ConsumerExceptionHandler implements ExceptionHandler<SofaTracerSpanEvent> { @Override public void handleOnStartException(Throwable ex) { SynchronizingSelfLog.error("AsyncConsumer occurs exception on start", ex); }  @Override void handleEventException(Throwable ex, long sequence, SofaTracerSpanEvent event); @Override void handleOnStartException(Throwable ex); @Override void handleOnShutdownException(Throwable ex);  }### Answer:
@Test public void handleOnStartException() throws IOException, InterruptedException { consumerExceptionHandler.handleOnStartException(new Throwable()); TestUtil.waitForAsyncLog(); File log = customFileLog("sync.log"); List<String> logs = FileUtils.readLines(log); assertTrue(logs.toString(), logs.get(0).contains("[ERROR]")); }