Jasmine-custom-message NPM

jasmine-custom-message

works with jasmine v1.3 (for work with jasmine v2 see jasmine2-custom-message)

This script makes it possible to use your own failure message on any jasmine assertion.

Example

describe('the story', function() {
  it('should finish ok', function() {
    since('all cats are grey in the dark').
    expect('tiger').toEqual('kitty'); // => 'all cats are grey in the dark'
  });
});

Simple

All the magic happens in since function. That returns an object with a property expect. That contains no more than a wrapped jasmine expect function. That returns jasmine expectation object with a specially defined message function. That can produce a custom failure message. That is generating based on a custom message you have supplied to since function as the first argument. That can be a primitive (except null and undefined), a function, or any other object. That is it.

Example

describe('test', function() {
  it('should be ok', function() {
    since(function() {
      return {'tiger': 'kitty'};
    }).
    expect(3).toEqual(4); // => '{"tiger":"kitty"}'
  });
});

Unobtrusive

You can use jasmine as you did before, since jasmine-custom-message does not replace global jasmine expect function.

Example

describe('test', function() {
  it('should be ok', function() {
    expect(3).toEqual(4); // => ordinary jasmine message
  });
});

Powerful

You can use expected and actual value of the assertion in your custom message, by:

Passing a function, and using this.actual and this.expected
Passing a string, and using #{actual} and #{expected}

Example using a function

describe('test', function() {
  it('should be ok', function() {
    since(function(expected) {
      return this.actual + ' =/= ' + expected;
    }).
    expect(3).toEqual(4); // => '3 =/= 4'
  });
});

Example using a string

describe('test', function() {
  it('should be ok', function() {
    since('#{actual} =/= #{expected}').
    expect(3).toEqual(4); // => '3 =/= 4'
  });
});

Moreover, you can use a promise as an argument of expect or matcher functions. Promise is recognized by then method, so be careful if your non-promise object has this method.

Example (with a little help of protractor)

describe('test', function() {
  it('should be ok', function() {
    since(function(expected) {
      return this.actual + ' =/= ' + expected;
    }).
    expect(protractor.promise.fulfilled(3)).toEqual(protractor.promise.fulfilled(4)); // => '3 =/= 4'
  });
});

Front-end usage

install the bower package from github

bower install jasmine-custom-message --save-dev

include jasmine-custom-message.js into your HTML file next to jasmine script

<script src="PATH-TO/jasmine.js"></script>
<script src="PATH-TO/jasmine-custom-message.js"></script>

Node.js usage

install the bower package

bower install jasmine-custom-message --save-dev

or npm package

npm install jasmine-custom-message --save-dev

require it in your spec file before your tests

require('jasmine-custom-message');

Change log

v0.8.0 - 2015.08.05 - Be careful of objects with then method, since they are treated as promises

fixed issue with custom failure messages on promised assertions
implemented "format string" functionality: #{actual} and #{expected}
configured protractor environment
corrected displaying of colors in tests running through protractor
updated specs

v0.7.0 - 2014.10.23

fixed issue with custom failure messages on inverse assertions
updated specs

v0.6.0 - 2014.01.18 - BROKEN COMPATIBILITY!

all the magic moved into newly introduced since function
restored automatic initiation of the script upon inclusion (browser) or require (Node.js)
cleaned specs

v0.5.0 - 2014.01.15