Testing with JEST and nock causing 'Cross origin null forbidden'

Question

I'm trying to test my service with JEST and mocking endpoint with nock. Service looks like this

export async function get(id) {
    const params = {
      mode: 'cors',
      headers: {
        'Accept': 'application/json',
        'Content-Type': 'application/json'
      }
    };

    let response = await fetch(`{$API}/projects/${id}`, params);

    return response.json();
}

Test:

import { 
  get 
} from './project';
import nock from 'nock';
const fetchNockProject = nock($API)
                          .get('/projects/1')
                          .reply('200', {});

      const data = await get(1);

      expect(data).resolves.toEqual(project);

When I run the test I get error:

console.error node_modules/jsdom/lib/jsdom/virtual-console.js:29 Error: Cross origin null forbidden

TypeError: Network request failed

Any idea why virtual-console is throwing this as this is only service.

score 31 · Answer 1 · edited Jul 03 '20 at 15:55

31

I found a solution for my problem which was connected with CORS. Nock mock should be:

fetchNockProject = nock($API)
                   .defaultReplyHeaders({
                      'access-control-allow-origin': '*',
                      'access-control-allow-credentials': 'true' 
                    })
                   .get('/projects/1')
                   .reply('200', project);

edited Jul 03 '20 at 15:55

Maksim Nesterenko

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answered Mar 21 '18 at 18:52

MarJano

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1

Thanks, you saved me ! – BraveVN Jun 22 '18 at 07:14
You are a hero. – Dan Zuzevich Aug 15 '18 at 15:19
Is nock() a javascript function? Can you provide the link? – Derzu Dec 06 '20 at 22:21

score 1 · Answer 2 · answered Oct 18 '18 at 20:09

1

Well, the posted answer didn't work for me and while I'm not saying it's wrong I thought I should share what did work for me.

In my case, my server is ASP.NET Core. I wasn't using the Cors middleware module that is provided. I added that in and configured it and that fixed my issue with no change to my javascript files.

answered Oct 18 '18 at 20:09

Frank V

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The OP was mocking fetch(), and so it's also necessary to mock the "access-control-allow-origin" header. Since you're connecting to a real server, you want the server to send a real such header (which is what the CORS middleware does) – Andy Mar 26 '20 at 14:35

Testing with JEST and nock causing 'Cross origin null forbidden'

2 Answers2