final User user = new User();
        assertNull(user.getRoomNumber());

        user.setRoomNumber("101");
        assertEquals("101", user.getRoomNumber());
    }

    @Test
    public void test_user_mobile() {
        final User user = new User();
        assertNull(user.getMobile());

        user.setMobile("555-1234");
        assertEquals("555-1234", user.getMobile());
    }

    @Test