### Question:
DalMultiMessageProducer { public abstract Transaction startTransactionAndGet(String type, String name);  static DalMultiMessageProducer createProducer(); static DalMultiMessageProducer createEmptyProducer(); abstract void startTransaction(String type, String name); abstract Transaction startTransactionAndGet(String type, String name); abstract void addTag(String key, String value); abstract void setTransactionStatus(Throwable throwable); abstract void setTransactionStatus(String status); abstract void completeTransaction(); abstract void completeAllTransaction(); abstract void continueTrace(String requestId, String rpcId); abstract void addPattern2CurTransaction(String pattern); abstract void addPattern2CurTransaction(String pattern, String sqlHash); abstract void clean(); abstract boolean isEmpty(); abstract String nextLocalRpcId(); abstract String nextRemoteRpcId(); abstract String currentRequestId(); abstract FluentEvent newFluentEvent(String type, String name); abstract Map<String, String> getAllDalTags();  }### Answer:
@Test public void testStartTransactionAndGet() throws Exception { DalMultiMessageProducer noop = DalMultiMessageProducer.createEmptyProducer(); DalMultiMessageProducer real = DalMultiMessageProducer.createProducer(); assertEquals(noop.startTransactionAndGet("DAL", "test.select"), null); assertTrue(Objects.nonNull(real.startTransactionAndGet("DAL", "test.select"))); }