### Question:
FlumeEventQueue { synchronized FlumeEventPointer removeHead(long transactionID) { if(backingStore.getSize() == 0) { return null; } long value = remove(0, transactionID); Preconditions.checkState(value != EMPTY, "Empty value " + channelNameDescriptor); FlumeEventPointer ptr = FlumeEventPointer.fromLong(value); backingStore.decrementFileID(ptr.getFileID()); return ptr; } FlumeEventQueue(EventQueueBackingStore backingStore, File inflightTakesFile,
          File inflightPutsFile); int getCapacity();  }### Answer:
@Test public void testQueueIsEmptyAfterCreation() throws Exception { queue = new FlumeEventQueue(backingStore, backingStoreSupplier.getInflightTakes(), backingStoreSupplier.getInflightPuts()); Assert.assertNull(queue.removeHead(0L)); }