### Question:
RouterUtils { static Pair<Account, Container> getAccountContainer(AccountService accountService, short accountId, short containerId) { Account account = accountService.getAccountById(accountId); Container container = account == null ? null : account.getContainerById(containerId); return new Pair<>(account, container); }    }### Answer:
@Test public void testGetAccountContainer() { AccountService accountService = new InMemAccountService(false, false); Pair<Account, Container> accountContainer = RouterUtils.getAccountContainer(accountService, Account.UNKNOWN_ACCOUNT_ID, Container.UNKNOWN_CONTAINER_ID); Assert.assertEquals("Account should be null", null, accountContainer.getFirst()); Assert.assertEquals("Container should be null", null, accountContainer.getSecond()); accountContainer = RouterUtils.getAccountContainer(accountService, Utils.getRandomShort(random), Utils.getRandomShort(random)); Assert.assertEquals("Account should be null", null, accountContainer.getFirst()); Assert.assertEquals("Container should be null", null, accountContainer.getSecond()); short accountId = Utils.getRandomShort(random); short containerId = Utils.getRandomShort(random); Account account = new AccountBuilder(accountId, "AccountNameOf" + accountId, Account.AccountStatus.ACTIVE).build(); accountService.updateAccounts(Arrays.asList(account)); accountContainer = RouterUtils.getAccountContainer(accountService, accountId, containerId); Assert.assertEquals("Account doesn't match", account, accountContainer.getFirst()); Assert.assertEquals("Container should be null", null, accountContainer.getSecond()); Container container = new ContainerBuilder(containerId, "ContainerNameOf" + containerId, Container.ContainerStatus.ACTIVE, "description", accountId).build(); account = new AccountBuilder(accountId, "AccountNameOf" + accountId, Account.AccountStatus.ACTIVE).addOrUpdateContainer( container).build(); accountService.updateAccounts(Arrays.asList(account)); accountContainer = RouterUtils.getAccountContainer(accountService, accountId, containerId); Assert.assertEquals("Account doesn't match", account, accountContainer.getFirst()); Assert.assertEquals("Container doesn't match", container, accountContainer.getSecond()); }