### Question:
StringAppender implements ItemAppender<LogEvent> { @Override public void start() { batchDelivery.start(); state = State.STARTED; } StringAppender(BatchDelivery batchDelivery, Function<LogEvent, String> serializer); @Override void append(String formattedIndexName, LogEvent logEvent); @Override void start(); @Override void stop(); @Override boolean isStarted(); @Override boolean isStopped();  }### Answer:
@Test public void lifecycleStartStartsBatchDelivery() { BatchDelivery batchDelivery = mock(BatchDelivery.class); ItemAppender itemAppender = new StringAppender(batchDelivery, logEvent -> null); itemAppender.start(); verify(batchDelivery).start(); }