我如何检查笑话测试是否在派遣动作创建者中执行了一个派遣动作? [英] How can I check in a jest test if a thunk action within a thunk action creator has been dispatched?

问题描述

这是一个广义的例子:

// myActions.js
export const actionOne = () => (dispatch) => {
    dispatch(actionTwo());
};

export const actionTwo = () => ({
    type: 'SOME_TYPE',
});

我想测试是否已调用actionTwo或已调度actionTwo，理想情况下，该测试不知道actionTwo发生了什么，因为我有一个不同的测试来处理该问题.

I would like to test that actionTwo has been either called or dispatched, ideally without the test knowing anything about what is going on in actionTwo, because I have a different test that takes care of that.

我正在使用redux-mock-store将已测试的动作分发到模拟商店，并调用store.getActions()来查找是否已分发了thunk动作创建者中的预期动作.我觉得这不是在这种情况下进行的正确方法，因为那样的话测试会测试更多的东西.我真的只想知道actionTwo是否已被调用.

I am using redux-mock-store to dispatch the tested action to a mocked store and calling store.getActions() to find out if the expected actions within the thunk action creator have been dispatched. I feel it is not the right way to go in this particular scenario because then the test would test more than it should. I really only want to know if actionTwo has been called at all.

我知道spyOn和jest.mock，但是我一直无法使用它们来解决我的问题.这是广义测试的样子:

I'm aware of spyOn and jest.mock, but I've been unable to use either to solve my problem. Here's what the generalized test looks like:

// myActions.test.js
import configureMockStore from 'redux-mock-store';
import thunk from 'redux-thunk';
import * as actions from 'myActions';

const mockStore = configureMockStore([thunk]);

test('actionOne', () => {
    const store = mockStore();

    return store.dispatch(actions.actionOne()).then(() => {
        // TODO: check if actions.actionTwo was called
    });
});

test('actionTwo', () => {
    const store = mockStore();

    return store.dispatch(actions.actionTwo()).then(() => {
        expect(store.getActions()).toEqual([{ type: 'SOME_TYPE' }]);
    }); 
});

我很感谢任何建议！

推荐答案

花了我一段时间，但我发现了.这不是理想的方法(因为它涉及到已测试代码的微小更改)，但是我可以获得的最接近理想的方法.

Took me a while, but I figured it out. It's not ideal (because it involves a small change to the tested code), but the closest to ideal that I could get.

// myActions.js
export const actionOne = () => (dispatch) => {
    dispatch(exports.actionTwo());
};

export const actionTwo = () => ({
    type: 'SOME_TYPE',
});

重要的更改是exports.actionTwo().这样，我确保可以从外部(测试文件)覆盖该函数的实现，并且覆盖函数实际上将在导入的文件中调用.

The important change is the exports.actionTwo(). That way, I make sure that I can overwrite the function's implementation from the outside (the test file) and the overwriting function will actually be called from within the imported file.

现在，我可以简单地将以下内容添加到我的测试文件中:

Now I can simply add something like the following to my test file:

beforeEach(() => {
    actions.actionTwo = jest.fn(() => () => Promise.resolve());
});

actionTwo现在正在被嘲笑，我可以在其上使用toBeCalledWith和其他期望.如果我想在同一测试文件中测试其实际实现，则可以在调用beforeEach之前将其存储在变量中，例如:

actionTwo is now being mocked and I can use toBeCalledWith and other expectations on it. If I wish to test its actual implementation within the same test file, I can store it in a variable before calling beforeEach, like:

const actionTwo = actions.actionTwo;

然后在其实现的测试设置中，我可以覆盖模拟调用

And then in the test setup for its implementation, I can overwrite the mock calling

actions.actionTwo = actionTwo;

就是这样.现在，我可以确保忽略导出函数的所有副作用，并将其作为实际单元进行测试.

That's it. Now I can make sure to ignore all side effects from an exported function and test it as an actual unit.

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