How do I test axios in Jest?

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:

• Jest mocking documentation
• A GitHub discussion that explains about the scope of the jest.mock("axios") line.
• Another answer of mine which addresses applying the techniques above to Axios request interceptors.

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

I could do that following the steps:

1. Create a folder __mocks__/ (as pointed by @Januartha comment)
2. Implement an axios.js mock file
3. 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;    })};