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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?

Answers

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