@Test public void testFindCustomerByEmail() { Customer c1 = new Customer(); String email = "*****@*****.**"; c1.setEmail(email); doReturn(c1).when(customerDaoMock).findByEmail(email); Customer customer = service.findCustomerByEmail(email); verify(customerDaoMock).findByEmail(email); verifyNoMoreInteractions(customerDaoMock); Assert.assertEquals(email, customer.getEmail()); }