Cannot read property of undefined thrown from running NPM and PACT

Question

I'm trying to follow the PACT workshop example with some alternate data.

This may be more of a Javascript/Node question but I'm a but stumped, as a novice.

Given a consumer.spec.js file of:

const chai = require('chai');
const nock = require('nock');
const chaiAsPromised = require('chai-as-promised');
const expect = chai.expect;
const API_PORT = process.env.API_PORT || 9123;
chai.use(chaiAsPromised);

const API_HOST = `http://localhost:${API_PORT}`;

describe('Consumer', () => {
  describe('when a call to the Provider is made', () => {
    const clothingStatus = 'hello';
    const {emailClothingOfferStatus} = require('../client');

    it('can process the HTML payload from the provider', () => {
      nock(API_HOST)
        .get('/provider')
        .query({validPermStatus:'hello'})
        .reply(200, {
          test:'NO',
          validPermStatus: clothingStatus,
          count: 1000,
        });

      const response = emailClothingOfferStatus(clothingStatus);

      return expect(response.body.clothingStatus).to.eventually.equal('hello')
    })
  })
});

and a client .js file of:

const request = require('superagent');
const API_HOST = process.env.API_HOST || 'http://localhost';
const API_PORT = process.env.API_PORT || 9123;
const API_ENDPOINT = `${API_HOST}:${API_PORT}`;

// Fetch provider data
const emailClothingOfferStatus = emailPermChoice => {
  let withEmailClothing = {};
  const emailClothingGrantedRegex = 'hello';

  if(emailPermChoice){
    console.log(emailPermChoice);
    withEmailClothing = {validPermStatus: emailPermChoice}
  }

  return request
    .get(`${API_ENDPOINT}/provider`)
    .query(withEmailClothing)
    .then(
      res => {
        if (res.body.validPermStatus.match(emailClothingGrantedRegex)) {
          return {
            clothingStatus: (res.body.validPermStatus),
          }
        } else {
          throw new Error('Could not verify email clothing offer status')
        }
      },
      err => {
        throw new Error(`Error from response: ${err.body}`)
      }
    )
};

module.exports = {
  emailClothingOfferStatus,
};

and I have the following in my package.json scripts:

"test:consumer": "./node_modules/.bin/mocha --timeout 150000 pact/consumer/test/consumer.spec.js",

When I run npm run test:consumer, I get:

1) Consumer
       when a call to the Provider is made
         can process the HTML payload from the provider:
     TypeError: Cannot read property 'clothingStatus' of undefined
      at Context.it (pact/consumer/test/consumer.spec.js:29:35)

I'm sure it's something obvious but can anyone help?

Answer 1

Two things stand out to me as a problem:

1. The test above is a normal unit test designed to show how unit tests won't catch contract issues, and leads you into why Pact is useful (In case this wasn't clear). In short, it's not a Pact test at all - I can tell because it's using Nock, meaning the expected requests will never reach Pact. I can also tell because the Pact package doesn't appear to be imported. You want to model from this file https://github.com/DiUS/pact-workshop-js/blob/master/consumer/test/consumerPact.spec.js
2. The response value is a Promise, which means you can't do return expect(response.body.clothingStatus).to.eventually.equal('hello') because response is a promise, so body will be undefined and clothingStatus is not a property of that. The chai eventually API is useful for this sort of test, but as I understand, it has to work directly with a Promise - you could do expect(response).to... and then chai can go to work.