How do I test axios in Jest?
JavascriptReactjsReact ReduxAxiosJestjsJavascript Problem Overview
I have this action in React:
export function fetchPosts() {
const request = axios.get(`${WORDPRESS_URL}`);
return {
type: FETCH_POSTS,
payload: request
}
}
How do I test Axios in this case?
Jest has this use case on their site for asynchronous code where they use a mock function, but can I do this with Axios?
Reference: An Async Example
I have done this so far to test that it is returning the correct type:
it('should dispatch actions with the correct type', () => {
store.dispatch(fetchPosts());
let action = store.getActions();
expect(action[0].type).toBe(FETCH_POSTS);
});
How can I pass in mock data and test that it returns?
Javascript Solutions
Solution 1 - Javascript
Without using any other libraries:
import * as axios from "axios";
// Mock out all top level functions, such as get, put, delete and post:
jest.mock("axios");
// ...
test("good response", () => {
axios.get.mockImplementation(() => Promise.resolve({ data: {...} }));
// ...
});
test("bad response", () => {
axios.get.mockImplementation(() => Promise.reject({ ... }));
// ...
});
It is possible to specify the response code:
axios.get.mockImplementation(() => Promise.resolve({ status: 200, data: {...} }));
It is possible to change the mock based on the parameters:
axios.get.mockImplementation((url) => {
if (url === 'www.example.com') {
return Promise.resolve({ data: {...} });
} else {
//...
}
});
Jest v23 introduced some syntactic sugar for mocking Promises:
axios.get.mockImplementation(() => Promise.resolve({ data: {...} }));
It can be simplified to
axios.get.mockResolvedValue({ data: {...} });
There is also an equivalent for rejected promises: mockRejectedValue
.
Further Reading:
-
A GitHub discussion that explains about the scope of the
jest.mock("axios")
line. -
A related question which addresses applying the techniques above to Axios request interceptors.
Solution 2 - Javascript
I used axios-mock-adapter. In this case the service is described in ./chatbot. In the mock adapter you specify what to return when the API endpoint is consumed.
import axios from 'axios';
import MockAdapter from 'axios-mock-adapter';
import chatbot from './chatbot';
describe('Chatbot', () => {
it('returns data when sendMessage is called', done => {
var mock = new MockAdapter(axios);
const data = { response: true };
mock.onGet('https://us-central1-hutoma-backend.cloudfunctions.net/chat').reply(200, data);
chatbot.sendMessage(0, 'any').then(response => {
expect(response).toEqual(data);
done();
});
});
});
You can see it the whole example here:
Service: https://github.com/lnolazco/hutoma-test/blob/master/src/services/chatbot.js
Test: https://github.com/lnolazco/hutoma-test/blob/master/src/services/chatbot.test.js
Solution 3 - Javascript
I could do that following the steps:
- Create a folder mocks/ (as pointed by @Januartha comment)
- Implement an
axios.js
mock file - Use my implemented module on test
The mock will happen automatically
Example of the mock module:
module.exports = {
get: jest.fn((url) => {
if (url === '/something') {
return Promise.resolve({
data: 'data'
});
}
}),
post: jest.fn((url) => {
if (url === '/something') {
return Promise.resolve({
data: 'data'
});
}
if (url === '/something2') {
return Promise.resolve({
data: 'data2'
});
}
}),
create: jest.fn(function () {
return this;
})
};
Solution 4 - Javascript
I've done this with nock, like so:
import nock from 'nock'
import axios from 'axios'
import httpAdapter from 'axios/lib/adapters/http'
axios.defaults.adapter = httpAdapter
describe('foo', () => {
it('bar', () => {
nock('https://example.com:443')
.get('/example')
.reply(200, 'some payload')
// test...
})
})
Solution 5 - Javascript
Look at this
- The function to test
album.js
const fetchAlbum = function () {
return axios
.get("https://jsonplaceholder.typicode.com/albums/2")
.then((response) => {
return response.data;
});
};
- The test
album.test.js
const axios = require("axios");
const { fetchAlbum } = require("../utils.js");
jest.mock("axios");
test("mock axios get function", async () => {
expect.assertions(1);
const album = {
userId: 1,
id: 2,
title: "sunt qui excepturi placeat culpa",
};
const payload = { data: album };
// Now mock axios get method
axios.get = jest.fn().mockResolvedValue(payload);
await expect(fetchAlbum()).resolves.toEqual(album);
});
Solution 6 - Javascript
For those looking to use axios-mock-adapter in place of the mockfetch example in the Redux documentation for async testing, I successfully used the following:
File actions.test.js:
describe('SignInUser', () => {
var history = {
push: function(str) {
expect(str).toEqual('/feed');
}
}
it('Dispatches authorization', () => {
let mock = new MockAdapter(axios);
mock.onPost(`${ROOT_URL}/auth/signin`, {
email: '[email protected]',
password: 'test'
}).reply(200, {token: 'testToken' });
const expectedActions = [ { type: types.AUTH_USER } ];
const store = mockStore({ auth: [] });
return store.dispatch(actions.signInUser({
email: '[email protected]',
password: 'test',
}, history)).then(() => {
expect(store.getActions()).toEqual(expectedActions);
});
});
In order to test a successful case for signInUser
in file actions/index.js:
export const signInUser = ({ email, password }, history) => async dispatch => {
const res = await axios.post(`${ROOT_URL}/auth/signin`, { email, password })
.catch(({ response: { data } }) => {
...
});
if (res) {
dispatch({ type: AUTH_USER }); // Test verified this
localStorage.setItem('token', res.data.token); // Test mocked this
history.push('/feed'); // Test mocked this
}
}
Given that this is being done with jest, the localstorage call had to be mocked. This was in file src/setupTests.js:
const localStorageMock = {
removeItem: jest.fn(),
getItem: jest.fn(),
setItem: jest.fn(),
clear: jest.fn()
};
global.localStorage = localStorageMock;