@Test
  public void testFindCustomerById() {
    Customer c1 = new Customer();
    c1.setId(1L);
    doReturn(c1).when(customerDaoMock).findById(1L);

    Customer customer = service.findCustomerById(1L);
    verify(customerDaoMock).findById(1L);
    verifyNoMoreInteractions(customerDaoMock);
    Assert.assertEquals(Long.valueOf(1), customer.getId());
  }