Javascript 如何测试您不知道的函数'；我无法直接访问

我正在尝试测试从

useReducer

解构的

dispatch

函数

我的分派函数是在我的组件中创建的，因此，据我所知，我不能像通常那样

expect（分派）

我的组件如下所示：

const reducer = (state, action) => {
    switch (action.type) {
        case 'MY_ACTION':
            return { ...state, myError: action.payload };
    }
};

const Container = ({ someProp, anotherProp, aThirdProp }) => {

    // This hook only works at this level of my application

    const onlyAvailableInsideContainer = useonlyAvailableInsideContainer();



    // Due to the above my initial state needs to be created here

    const initialState = {
        initialStateArr: [],
        someProp,
        myError: null,
        aThirdProp,
        anotherProp,
        onlyAvailableInsideContainer,
    };



    // Which means I need to extract my state and dispatch functions within the Container also

    const [state, dispatch] = useReducer(reducer, initialState);

    const { fieldProps, formProps, errors } = someHook(
        hookConfig(state, dispatch, aThirdProp, onlyAvailableInsideContainer),
    );

    return (
        <div className="dcx-hybrid">
            <MyContext.Provider
                value={{ state, dispatch, fieldProps, formProps, errors }}
            >
                <SomeChildComponent />
            </MyContext.Provider>
        </div>
    );
};

const dispatch= jest.fn();
const useReducerMock= (reducer,initialState) => [initialState, dispatch];
jest.spyOn(React, 'useReducer').mockImplementation(useReducerMock);

试着像这样监视
useReducer
：

const reducer = (state, action) => {
    switch (action.type) {
        case 'MY_ACTION':
            return { ...state, myError: action.payload };
    }
};

const Container = ({ someProp, anotherProp, aThirdProp }) => {

    // This hook only works at this level of my application

    const onlyAvailableInsideContainer = useonlyAvailableInsideContainer();



    // Due to the above my initial state needs to be created here

    const initialState = {
        initialStateArr: [],
        someProp,
        myError: null,
        aThirdProp,
        anotherProp,
        onlyAvailableInsideContainer,
    };



    // Which means I need to extract my state and dispatch functions within the Container also

    const [state, dispatch] = useReducer(reducer, initialState);

    const { fieldProps, formProps, errors } = someHook(
        hookConfig(state, dispatch, aThirdProp, onlyAvailableInsideContainer),
    );

    return (
        <div className="dcx-hybrid">
            <MyContext.Provider
                value={{ state, dispatch, fieldProps, formProps, errors }}
            >
                <SomeChildComponent />
            </MyContext.Provider>
        </div>
    );
};

const dispatch= jest.fn();
const useReducerMock= (reducer,initialState) => [initialState, dispatch];
jest.spyOn(React, 'useReducer').mockImplementation(useReducerMock);

然后测试它：

   expect(dispatch).toBeCalledWith({
        type: 'MY_ACTION',
        payload: 'Some error message.',
    });

测试通话的结果，而不是通话本身。@HereticMonkey我已经这样做了-我的问题是我的覆盖率表中仍然有漏行：（你是怎么做到的？遗漏了哪些行？@jornsharpe的方式与上述方式非常相似。我检查是否存在呈现点击后/分派的元素。但在实际情况下，我仍然会在我的还原器中找到未覆盖的行。请确保你的测试正在执行函数的所有可能输入，或者在你的情况下，所有输入对生成子函数的可能输入的父函数。我强烈建议不要监视React的某些部分-不要模仿你没有的。@jonrsharpe你是对的，但他想测试函数调用，最好测试此操作的ui。