Reactjs 使用jest和enzymne测试自定义react挂钩时出错

当将自定义钩子与jest和enzymne一起使用时，我会遇到以下错误“TypeError:无法读取未定义的”属性“Symbol（Symbol.iterator）”

尝试了各种各样的事情，但似乎没有任何效果。请帮忙

import React, { useEffect, useState, Fragment } from 'react';

/* Utils */
import { useSystemContext } from '../../../utils/Context/SystemContextProvider';

/* Components */
import MenuStructure from './MenuStructure';

const Menu = () => {
    const [{ siteData }] = useSystemContext();
    const [open, setOpen] = React.useState(false);

    const openMenu = () => {
        setOpen(!open);
    };

    const componentProps = {
        menuItems: siteData,
        openMenu: openMenu,
        open: open
    };

    return (
        <MenuStructure {...componentProps} />
    )
};

export default Menu;

根据请求添加了useSystemContext

import React, { createContext, useContext, useReducer } from 'react';

export const SystemContext = createContext();

export const SystemContextProvider = ({ reducer, initialState, children }) => (
    <SystemContext.Provider value={useReducer(reducer, initialState)}>
        {children}
    </SystemContext.Provider>
);

export const useSystemContext = () => useContext(SystemContext);

---

import React，{createContext，useContext，useReducer}来自“React”；
export const SystemContext=createContext（）；
export const SystemContextProvider=（{reducer，initialState，children}）=>(
{儿童}
);
export const useSystemContext=（）=>useContext（SystemContext）；

---

这在站点运行时可以正常工作

显示

useSystemContext

当然，这里是来自“React”的代码

import React，{createContext，useContext，useReducer}；export const SystemContext=createContext（）；export const SystemContextProvider=（{reducer，initialState，children}）=>（{children}）；export const useSystemContext=（）=>useContext（SystemContext）请使用“编辑”按钮编辑您的问题，不要将其作为无法阅读的评论发布。对不起，我现在就添加它
TypeError: Cannot read property 'Symbol(Symbol.iterator)' of undefined

       9 | import MenuStructure from './MenuStructure';
      10 | 
    > 11 | const Menu = () => {
         |                    ^
      12 |     const [{ siteData }] = useSystemContext();
      13

import React, { createContext, useContext, useReducer } from 'react';

export const SystemContext = createContext();

export const SystemContextProvider = ({ reducer, initialState, children }) => (
    <SystemContext.Provider value={useReducer(reducer, initialState)}>
        {children}
    </SystemContext.Provider>
);

export const useSystemContext = () => useContext(SystemContext);