@Test
  public void testConflictingUpdateCaseE() throws Exception {
    accountService = mockHelixAccountServiceFactory.getAccountService();
    // write two accounts (1, "a") and (2, "b")
    writeAccountsForConflictTest();
    Collection<Account> conflictAccounts =
        Collections.singleton((new AccountBuilder((short) 1, "b", AccountStatus.INACTIVE).build()));
    assertUpdateAccountsFails(conflictAccounts, AccountServiceErrorCode.ResourceConflict, accountService);
    assertEquals("Wrong account number in HelixAccountService", 2, accountService.getAllAccounts().size());
    assertEquals("Wrong account name got from HelixAccountService", "a",
        accountService.getAccountById((short) 1).getName());
  }
Tests updating a {@link Account}, which has the same id as an existing record, but the name conflicting with
another existing record. The update operation will fail. This test corresponds to case E specified in the JavaDoc
of {@link AccountService}.
@throws Exception Any unexpected exception.
ambry-account/src/test/java/com/github/ambry/account/HelixAccountServiceTest.java