Testing async action creator (using axios) in Redux with Jest - asynchronous

Question

I have an issue creating a test for my async action creator in Redux. I am using axios for fetching and Jest for testing. Data is loaded correctly in the app itself. Just the test which I am writing is going all wrong ...
I followed Redux documentation concerning testing, but it is fetchMock used there. I have trouble transferring it to my case.
I tried two approaches which are both failing:
using moxios to mock axios
using jest.mock('axios'),
This is the code in my action creator:
import {
BG_LOAD_START,
BG_LOAD_SUCCESS,
BG_LOAD_FAILURE} from './types'
import axios from 'axios'
export const bgLoad = (url, pictureNumber=0) => {
return dispatch => {
dispatch(bgLoadStart());
return axios.get(url, {
headers: {
Authorization: `Bearer ${process.env.REACT_APP_API_KEY}`
}
})
.then(res => dispatch(bgLoadSuccess(res.data.photos[pictureNumber], res.data.name, res.data.url)))
.catch(err => dispatch(bgLoadFailure(err)))
}
}
const bgLoadStart = () => {
return {
type: BG_LOAD_START
}
}
const bgLoadSuccess = (bgImage, name, url) => {
return {
type: BG_LOAD_SUCCESS,
payload: {
bgImage,
name,
url
}
}
}
const bgLoadFailure = error => {
return {
type: BG_LOAD_FAILURE,
payload: {
...error
}
}
}
and here is what I have in my test:
import configureStore from 'redux-mock-store'
import thunk from 'redux-thunk'
import {BG_LOAD_START, BG_LOAD_SUCCESS} from '../types'
import {bgLoad} from '../bgLoad'
import moxios from 'moxios'
const middlewares = [thunk];
const mockStore = configureStore(middlewares);
// jest.mock('axios');
describe(`async bgLoad action`, ()=> {
beforeEach(()=>{
moxios.install()
})
afterEach(()=>{
moxios.uninstall()
})
it(`creates BG_LOAD_SUCCESS when data has been fetched`, ()=> {
const fetchedData = [{
image: 'this is example image',
name: 'my name is image',
url: 'this is example link'
}]
moxios.wait(()=>{
const request = moxios.requests.mostRecent();
request.respondWith({
status: 200,
response: fetchedData
})
})
// axios.get.mockResolvedValue(fetchedData);
const expectedActions = [
{type: BG_LOAD_START},
{type: BG_LOAD_SUCCESS,
payload: {
bgImage: fetchedData[0].image,
name: fetchedData[0].name,
url: fetchedData[0].url,
}
}
]
const store = mockStore({});
return store.dispatch(bgLoad()).then(()=>{
expect(store.getActions()).toEqual(expectedActions)
})
})
})
Here is the response with which I am getting from the console:
Expected value to equal:
[{"type": "BG_LOAD_START"}, {"payload": {"bgImage": "this is example image", "name": "my name is image", "url": "this is example link"}, "type": "BG_LOAD_SUCCESS"}]
Received:
[{"type": "BG_LOAD_START"}, {"payload": {}, "type": "BG_LOAD_FAILURE"}]

Answer 1

Here is the solution use jest.mock:
actionCreators.ts:
import { BG_LOAD_START, BG_LOAD_SUCCESS, BG_LOAD_FAILURE } from './types';
import axios from 'axios';
export const bgLoad = (url, pictureNumber = 0) => {
return dispatch => {
dispatch(bgLoadStart());
return axios
.get(url, {
headers: {
Authorization: `Bearer ${process.env.REACT_APP_API_KEY}`
}
})
.then(res => dispatch(bgLoadSuccess(res.data.photos[pictureNumber], res.data.name, res.data.url)))
.catch(err => dispatch(bgLoadFailure(err)));
};
};
const bgLoadStart = () => {
return {
type: BG_LOAD_START
};
};
const bgLoadSuccess = (bgImage, name, url) => {
return {
type: BG_LOAD_SUCCESS,
payload: {
bgImage,
name,
url
}
};
};
const bgLoadFailure = error => {
return {
type: BG_LOAD_FAILURE,
payload: {
...error
}
};
};
actionCreators.spec.ts:
import configureStore from 'redux-mock-store';
import thunk, { ThunkDispatch } from 'redux-thunk';
import axios from 'axios';
import { BG_LOAD_START, BG_LOAD_SUCCESS } from './types';
import { bgLoad } from './actionCreators';
import { AnyAction } from 'redux';
const middlewares = [thunk];
const mockStore = configureStore<any, ThunkDispatch<{}, any, AnyAction>>(middlewares);
jest.mock('axios', () => {
return {
get: jest.fn()
};
});
describe(`async bgLoad action`, () => {
const fetchedData = [
{
image: 'this is example image',
name: 'my name is image',
url: 'this is example link'
}
];
afterEach(() => {
jest.resetAllMocks();
});
it(`creates BG_LOAD_SUCCESS when data has been fetched`, () => {
(axios.get as jest.MockedFunction<typeof axios.get>).mockResolvedValueOnce({
data: { photos: [fetchedData[0].image], name: fetchedData[0].name, url: fetchedData[0].url }
});
const expectedActions = [
{ type: BG_LOAD_START },
{
type: BG_LOAD_SUCCESS,
payload: {
bgImage: fetchedData[0].image,
name: fetchedData[0].name,
url: fetchedData[0].url
}
}
];
const store = mockStore({});
return store.dispatch(bgLoad('https://github.com/mrdulin')).then(() => {
expect(store.getActions()).toEqual(expectedActions);
expect(axios.get).toBeCalledWith('https://github.com/mrdulin', {
headers: {
Authorization: `Bearer ${process.env.REACT_APP_API_KEY}`
}
});
});
});
});
Unit test result with coverage report:
PASS src/stackoverflow/55966274/actionCreators.spec.ts
async bgLoad action
✓ creates BG_LOAD_SUCCESS when data has been fetched (20ms)
-------------------|----------|----------|----------|----------|-------------------|
File | % Stmts | % Branch | % Funcs | % Lines | Uncovered Line #s |
-------------------|----------|----------|----------|----------|-------------------|
All files | 88.89 | 50 | 71.43 | 88.24 | |
actionCreators.ts | 86.67 | 50 | 71.43 | 85.71 | 15,37 |
types.ts | 100 | 100 | 100 | 100 | |
-------------------|----------|----------|----------|----------|-------------------|
Test Suites: 1 passed, 1 total
Tests: 1 passed, 1 total
Snapshots: 0 total
Time: 4.774s, estimated 6s
Here is the completed demo: https://github.com/mrdulin/jest-codelab/tree/master/src/stackoverflow/55966274