Nock does not returns the setted headers

Question

I'm using Nock to intercept a http request.

test.js:

const nock = require('nock');
const server = require('../server');
const request = require('request');

describe('My test', () =>{
   it('Should returns the customized header', () => {
      nock('url')
      .get('/test')
      .reply(302, {
         'user-agent': 'Mozilla'
       })

      const { headers } = await request(server).get('/test');
      expect(headers['user-agent']).to.include('Mozilla');

   }
})

When I run the test, it fails and the log of headers received by request is like that:

 { 

 'user-agent': 'node-superagent/3.8.3',
  location: 'undefined',
  vary: 'Accept, Accept-Encoding',
  'content-type': 'text/plain; charset=utf-8',
  'content-length': '31',
  date: 'Fri, 24 May 2019 09:15:46 GMT',
  connection: 'close' 
 }

Do I missed something or it's the normal behaviour of Nock?

Answer 1

The issue is with the way you're passing the headers to the reply function. Headers are the third argument for that method, but you're providing them as the second arg which means the object with the the user-agent key is being used as the body. Since it's a 302 and you probably want an empty body, you should pass an empty string as the second arg.

nock('url')
  .get('/test')
  .reply(302, '', {
    'user-agent': 'Mozilla'
  })

Related docs.