### Question:
AccountServiceImpl implements AccountService { @Override public void transfer(String from, String to, double money) { double fromMoney = mapper.queryMoney(from); mapper.update(from, fromMoney - money); double toMoney = mapper.queryMoney(to); mapper.update(to, toMoney + money); }  @Override void transfer(String from, String to, double money);  }### Answer:
@Test public void testTransfer() { accountService.transfer("张三", "李四", 100); }