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测试Redux Thunk Action Creator

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我有一个redux动作创建者利用redux-thunk做一些逻辑来确定要分发到商店的内容 . 它不是基于承诺的,就像HTTP请求一样,所以我在如何正确测试它时遇到了一些问题 . 我需要测试当值满足条件时以及何时不满足条件 . 由于动作创建者没有返回承诺,我不能在我的测试中运行.then() . 测试这样的东西的最佳方法是什么?

同样,我相信测试getRemoveFileMetrics()动作创建者会非常简单,因为它确实会返回一个promise . 但是,如果值为removeFiles并满足条件,我该如何断言将调用?怎么能在测试中写出来?

提前谢谢,因为这让我在最近几天陷入困境 .

Action Creators

export const handleSelection = (value, cacheKey) => {
    return dispatch => {
        if (value === "removeFiles") {
            dispatch(getRemoveFileMetrics(cacheKey));
        }
        dispatch({ type: HANDLE_SELECTION, value });
    };
};

export const getRemoveFileMetrics = cacheKey => {
    return dispatch => {
        dispatch({ type: IS_FETCHING_DELETE_METRICS });
        return axios
            .get(`../GetRemoveFileMetrics`, { params: { cacheKey } })
            .then(response => {
                dispatch({ type: GET_REMOVE_FILE_METRICS, payload: response.data });
            })
            .catch(err => console.log(err));
    };
};

Jest

it("should dispatch HANDLE_SELECTION when selecting operation", () => {
    const store = mockStore({});
    const value = "switchVersion";
    const expectedAction = [{
        type: MOA.HANDLE_SELECTION,
        value,
    }]; // TypeError: Cannot read property 'then' of undefined
    return store.dispatch(MOA.handleSelection(value)).then(() => {
        const returnedActions = store.getActions();
        expect(returnedActions).toEqual(expectedAction);
    });
});

NEW EDIT

因此,基于Danny Delott回复承诺的答案,我实现了如下通过测试:

export const handleSelection = (value, cacheKey) => {
    return dispatch => {
        if (value === "removeFiles") {
            return dispatch(getRemoveFileMetrics(cacheKey));
        }
        return new Promise((resolve, reject) => {
            resolve(dispatch({ type: HANDLE_SELECTION, value }));   
        });
    };
};

1 回答

  • 1

    是否有理由明确不在您的动作创建者中返回承诺?看起来 getRemoveFileMetrics 正在返回承诺,它只是被 handleSelection 吞噬了......

    最简单的解决方案就是回报承诺:

    export const handleSelection = (value, cacheKey) => {
        return dispatch => {
            if (value === "removeFiles") {
                return dispatch(getRemoveFileMetrics(cacheKey));
            }
            dispatch({ type: HANDLE_SELECTION, value });
            return new Promise();
        };
    };
    

    否则,您需要在事件循环结束后进行断言 . 您可以使用包含在Promise中的setTimeout来获取 .then 行为 .

    it("should dispatch HANDLE_SELECTION when selecting operation", () => {
        const store = mockStore({});
        const value = "switchVersion";
        const expectedAction = [{
            type: MOA.HANDLE_SELECTION,
            value,
        }];
    
       store.dispatch(MOA.handleSelection(value));
    
       // flush outstanding async tasks
       return new Promise(resolve => {
         setTimeout(resolve, 0);
       })
       .then(() => {
          const returnedActions = store.getActions();
          expect(returnedActions).toEqual(expectedAction);
        });
    });
    

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