JUnit:测试父子实体

我有一个实体菜单,有一个儿童关系餐厅。我会检查是否有餐厅有菜单,菜单不能删除,所以我做了这个junit测试:

    Restaurant resto = new Restaurant(menu);
    restaurantService.save(resto);

            menuService.delete  (menu);

            menu = menuService.findByMenuId(menuName);

assertNotNull (menu);

但是我当然不能测试这个用户案例,因为我有这个例外:

Caused by: com.mysql.jdbc.exceptions.jdbc4.MySQLIntegrityConstraintViolationException: Cannot delete or update a parent row: a foreign key constraint fails 



public class Menu {

...


@OneToMany(mappedBy = "menu", 
               cascade = CascadeType.ALL, 
               orphanRemoval = true, fetch = FetchType.LAZY)
    @JsonIgnore
    private Set<Restaurants> restaurant = new HashSet<>();
...
}

和

public class Restaurant {

@ManyToOne(fetch = FetchType.EAGER)
    @JoinColumn(name = "menu_id")
    @JsonIgnore
    private Menu topMenu;
..
}