CustomerServiceTest.java

  @Test
  public void findCustomer() {
    Customer customer = mock(Customer.class);
    CustomerRepository repository = mock(CustomerRepository.class);
    CustomerService service = new CustomerService(repository);
    
    when(repository.find(anyLong())).thenReturn(customer);
    
    service.find(1L);

    verify(repository, times(1)).find(anyLong());
    verifyNoMoreInteractions(repository);
  }
  
  @Test(expected = NoResultException.class)
  public void findCustomerWithoutResult() {
    CustomerRepository repository = mock(CustomerRepository.class);
    CustomerService service = new CustomerService(repository);
    
    doThrow(NoResultException.class).when(repository).find(anyLong());
    
    service.find(1L);
  }