Stub HTTP request with Sinon

stub-http-request.js

import expect from 'expect'
import fs from 'fs'
import http from 'http'
import sinon from 'sinon'
import { parseString } from 'xml2js'

const parseXML = (url, callback) => {
  parseXML.get(
    url,
    (err, res, xml) => {
      if (err) throw err
      parseString(
        xml,
        (err, data) => {
          if (err) throw err
          callback(data)
        }
      )
    }
  )
}
parseXML.get = (url, callback) => {
  const req = http.get(
    url,
    res => {
      let buf = new Buffer('', 'utf8')
      res.on(
        'data',
        chunk => buf = Buffer.concat([
          buf,
          new Buffer(chunk, 'utf8')
        ])
      )
      res.on(
        'end',
        () => callback(
          undefined,
          res,
          buf.toString()
        )
      )
    }
  )
  req.on('error', err => callback(err))
}

describe('parseXML', () => {
  let spy

  before(done => {
    spy = sinon.stub(
      parseXML,
      'get',
      (url, callback) => {
        expect(url)
          .toEqual('http://hoge')
        callback(
          undefined,
          undefined,
          '<hoge>hoge</hoge>'
        )
      }
    )
    done()
  })
  after(done => {
    parseXML.get.restore()
    done()
  })

  it('should fetch XML and return parsed data', done => {
    parseXML(
      'http://hoge',
      data => {
        expect(spy.callCount)
          .toEqual(1)
        expect(data)
          .toEqual({ hoge: 'hoge' })
        done()
      }
    )
  })
})