What is the difference between chai and chai as promised

Question

What is the difference between chai and chai as promised in mocha framework while using protractor ?

Priyanshu · Answer 1 · 2016-07-25T12:41:48.013

Chai - Test Assertion Library which allows you to test your code with keywords such as expect, should etc. But while using Chai you have to take care of promises. For example

var expect = require('chai').expect;

it('should display correct tile', function() {
  var blah = 'foo';

  var title = browser.getTitle();

  return title.then(function(actualTitle) {
    expect(actualTitle).to.equal(expectedTitle);
  });
});

On the other hand if you use chai as promised then you do not need to handle promises explicitly. That could be done with the help of Chai as promised library. For example;

var chai = require('chai');
var expect = chai.expect;

var chaiAsPromised = require('chai-as-promised');
chai.use(chaiAsPromised);

it('should display correct title', function() {

  var actualTitle = browser.getTitle();

  return expect(actualTitle).to.eventually.equal(expectedTitle);
});

Thanks a lot for the example. – Emna Ayadi Apr 26 '16 at 07:45 — Emna Ayadi, Apr 26 '16 at 07:45

score 3 · Accepted Answer · answered Apr 25 '16 at 18:18

3

Chai is a BDD assertion library - providing you with common keywords such as assert or should etc.

Chai as Promised is an extension of that library specifically made to handle assertions with promises (as opposed to resolving them manually yourself).

https://github.com/domenic/chai-as-promised/

answered Apr 25 '16 at 18:18

Gunderson

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Thanks for your answer – Emna Ayadi Apr 26 '16 at 07:46

score 1 · Answer 3 · answered Apr 25 '16 at 18:15

1

It helps you test code that uses Promises. These can be tricky to test since they rely on callbacks to be executed and are generally async. This writeup might help you: http://www.sitepoint.com/promises-in-javascript-unit-tests-the-definitive-guide/

answered Apr 25 '16 at 18:15

pherris

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Thanks for your answer, So to test an angular js app is it better to use jasmine or Mocha framework with protractor? – Emna Ayadi Apr 26 '16 at 08:05
1

@Emna The Protractor docs recommend Jasmine, though both are supported. – Gunderson Apr 26 '16 at 10:31
@Gunderson Yes this what i'm searching what is recommended, thanks :) – Emna Ayadi Apr 26 '16 at 10:42

What is the difference between chai and chai as promised

3 Answers3