CODEWITHSUNDEEP
reactjsjestjs
Borduhh
Borduhh

Reputation: 2185

Mocking Axios with Jest in React - mock function not being called

I am trying to use Jest for unit testing. Part of the testing is to mock Axios, but for some reason it is not being called.

Here is my /__mocks__/axios.js code:

export default {
  post: jest.fn(() => Promise.resolve({})),
};

Here is my test code:

import mockAxios from 'axios';
import { registerUser } from '../../actions/auth';
import user from '../fixtures/user';


describe('Register User', () => {
  test('Should call register API and redirect to login', async () => {
    const historyMock = { push: jest.fn() };

    mockAxios.post.mockImplementationOnce(() => Promise.resolve());

    await registerUser(user, historyMock);

    expect(mockAxios.post).toHaveBeenCalledTimes(1);

  });
});

Also here is the registerUser code:

export const registerUser = (user, history) => dispatch => axios
  .post('/users/register', user)
  .then(() => history.push('/login'))
  .catch((err) => {
    dispatch(handleError(err));
  });

But for some reason I continue to get the error:

Register User › Should call register API and redirect to login

    expect(jest.fn()).toHaveBeenCalledTimes(1)

    Expected mock function to have been called one time, but it was called zero times.

      35 |     await registerUser(user, historyMock);
      36 | 
    > 37 |     expect(mockAxios.post).toHaveBeenCalledTimes(1);

Any ideas why the mock is not working?

Upvotes: 3

Views: 11569

Answers (2)

Borduhh
Borduhh

Reputation: 2185

As @jonrsharpe pointed out in the comments, the registerUser function was returning the function: 

dispatch => axios
  .post('/users/register', user)
  .then(() => history.push('/login'))
  .catch((err) => {
    dispatch(handleError(err));
  });

So in order for this to work, I had to had to mock the store using the redux-mock-store npm module. The new test code looks like: 

import mockAxios from 'axios';
import configureMockStore from 'redux-mock-store';
import thunk from 'redux-thunk';

import { setCurrentUser, registerUser } from '../../actions/auth';
import user from '../fixtures/user';

const defaultStoreState = { errors: {}, auth: { isAuthenticated: false, user: {} } };
const createMockStore = configureMockStore([thunk]);

describe('Register User', () => {
  test('Should call register API and redirect to login', (done) => {
    const mockStore = createMockStore(defaultStoreState);
    const historyMock = { push: jest.fn() };

    mockStore.dispatch(registerUser(user, historyMock)).then(() => {
      expect(mockAxios.post).toHaveBeenCalledTimes(1);
      expect(historyMock.push).toHaveBeenCalledTimes(1);
      expect(historyMock.push).toHaveBeenCalledWith('/login');

      done();
    });
  });
});

This gives a passing test now.

Upvotes: 2

jasonseminara
jasonseminara

Reputation: 415

I don't think you're setting the mock correctly. 

mockAxios.post.mockImplementationOnce

should be changed to 

mockAxios.post = jest.fn().mockResolvedValueOnce('bloofblurg');

Then you can double-check that post has been called once and resolved the expected value.

expect(mockAxios.post).resolves.toBe('bloofblurg');

see

  1. https://jestjs.io/docs/en/mock-function-api#mockfnmockresolvedvalueoncevalue
  2. https://jestjs.io/docs/en/expect#resolves

Upvotes: 1

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