public List<Role> memberRoles(Admin admin) {
        List<Role> memberRoles = new ArrayList<>();
        for (Role role : this) {
            if (admin.belongsTo(role)) {
                memberRoles.add(role);
            }
        }
        return memberRoles;
    }
@Test
    public void shouldListItselfWhenARoleExists() {
        Role firstRole = new RoleConfig(new CaseInsensitiveString("role1"), new RoleUser(new CaseInsensitiveString("USER1")), new RoleUser(new CaseInsensitiveString("user2")));
        Role secondRole = new RoleConfig(new CaseInsensitiveString("ROLE2"), new RoleUser(new CaseInsensitiveString("user1")), new RoleUser(new CaseInsensitiveString("user3")));
        RolesConfig rolesConfig = new RolesConfig(firstRole, secondRole);
        assertThat(rolesConfig.memberRoles(new AdminRole(new CaseInsensitiveString("role1"))), is(List.of(firstRole)));
        assertThat(rolesConfig.memberRoles(new AdminRole(new CaseInsensitiveString("role2"))), is(List.of(secondRole)));
    }