我有以下设置来测试异步功能。
首先,我的文件夹结构:
src/
├── App.vue
├── api
│ ├── __mocks__
│ │ └── api.js
│ └── api.js
├── components
│ ├── ...
├── main.js
└── store
├── __tests__
│ └── actions.spec.js
├── actions.js
├── getters.js
├── index.js
├── mutation-types.js
└── mutations.js
然后我的actions.spec.js
:
import * as types from '@/store/mutation-types';
import api from '@/api/api';
import {
fetchItems,
requestItems,
saveQuestion,
vote,
} from '../actions';
jest.mock('@api/api');
describe('fetchItems Action', () => {
let state;
let commit;
let dispatch;
beforeAll(() => {
commit = jest.fn();
dispatch = jest.fn();
state = {
apiEntryPoint: '',
nextPage: 0,
};
});
beforeEach(() => {
fetchItems({
commit,
dispatch,
state,
});
});
it('should call a commit before fetching', () => {
expect(commit).toHaveBeenCalledWith(types.PRE_HTTP_REQUEST);
});
it('should call receiveItems after succesful fetch', () => {
setTimeout(() => {
expect(dispatch).toHaveBeenCalledWith('receiveItems', {});
});
});
it('should call a fail commit if request fails', () => {
api.fetchItems = jest.fn(() => Promise.reject());
setTimeout(() => {
expect(commit).toHaveBeenCalledWith(types.FETCHED_ADS_FAIL);
});
});
});
api/api.js
import axios from 'axios';
axios.defaults.baseURL = 'https://polls.apiblueprint.org/';
const getUrl = () => (
axios('/')
.then(response => response.data.questions_url)
.catch((err) => {
throw err;
})
);
const fetchItems = (url, page = 1) => (
axios(url, { params: { page } })
.then(response => response.data)
.catch((err) => {
throw err;
})
);
export default {
fetchItems, getUrl,
};
和api/__mocks__/api.js
const getUrl = jest.fn(() => Promise.resolve());
const fetchItems = jest.fn(() => Promise.resolve());
export default {
fetchItems, getUrl
};
我的问题:
PASS src / components / QuestionsList / QuestionsList.spec.js PASS src / components / Question / Question.spec.js(node:48568)UnhandledPromiseRejectionWarning:未处理的promise promise(拒绝id:9):错误:错误:网络错误(节点: 48568)[DEP0018]弃用警告:已弃用未处理的承诺拒绝。将来,未处理的承诺拒绝将使用非零退出代码终止Node.js进程。 (节点:48568)UnhandledPromiseRejectionWarning:未处理的承诺拒绝(拒绝ID:10):错误:错误:网络错误PASS src / store / tests / actions.spec.js
toHaveBeenCalledWith()
”的参数,我的测试也会通过。在使用setTimeout的测试中,您需要使用done
回调。
目前,Jest正在运行测试并在没有错误的情况下到达终点。对于Jest来说,这意味着测试已经过去了。让Jest异步运行测试的一种方法是使用done
回调。
如果测试具有完成回调,则Jest将不会通过测试,直到调用完成回调为止。
您的代码应如下所示:
it('should call a fail commit if request fails', (done) => {
api.fetchItems = jest.fn(() => Promise.reject());
setTimeout(() => {
expect(commit).toHaveBeenCalledWith(types.FETCHED_ADS_FAIL);
done()
});
});
你可以在Jest docs(http://facebook.github.io/jest/docs/en/asynchronous.html#callbacks)中了解[完成回调。
Jest还有其他一些与asynchronous code交易的方式。