### Question:
AccountService { public boolean isAccountPresent(Long id) { return repository.existsById(id); }  boolean isAccountPresent(Long id); Account getAccountById(Long id); List<Account> getAccounts(); Account addAccount(Account account); Account updateAccount(Long id, Account account); void deleteAccount(Long id);  }### Answer:
@Test public void whenAccountIsPresentThenItShouldReturnTrue() { Long id = new Long(1); when(repository.existsById(id)).thenReturn(true); assertTrue(service.isAccountPresent(id)); }