Karma-polymer NPM

Karma adapter for Polymer framewrok

This adapter helps to test Polymer projects with Karma.

Tested with Chrome 37 and Firefox 32 on linux

Installation

Add npm module to your dependencies:

{
  "devDependencies": {
    "karma": "~0.12.0",
    "karma-polymer": "~0.1.3"
  }
}

or install it from command line:

npm install karma-polymer --save-dev

Configuration

Note to add polymer before test framework (jasmine for example).

Add polymer to frameworks array and specify your platform.js, polymer.html and project modules:

// karma.conf.js
module.exports = function(config) {
  config.set({
    frameworks: ['polymer', 'jasmine'],

    files: [
      // necessary for nested imports
      { pattern: 'bower_components/**', included: false, served: true, watched: true },
      'test/**/*Spec.js'
    ],

    polymer: {
      platform: 'bower_components/platform/platform.js',
      src: [
        'bower_components/polymer/polymer.html',
        'src/*.html'
      ]
    },
  });
};

Polymer adapter will add your modules to files array as served, but it can't detect any other imports inside this modules, so you should specify their manually (see nested imports above).

Usage

The polymer adapter creates necessary script element for load platform.js and a set of specified import elements (don't forget to specify polymer.html itself).

Polymer adapter provides usefull object polymer in global space:

polymer.create(el1, el2, ..., callback)

Creates polymer elements

This function takes a list of elements to create and callback function as a last argument. You can pass just a tag name of element or entire html code with nested elements. Callback will be called with all top-level created elements as arguments when polymer will be ready.

Callback is usefull for jasmine async resolve:

beforeEach(function(done) {
  polymer.create('my-test-element', done)
})

it('should be true', function(done) {
  polymer.create('<x-el><span>test</span></x-el>', function(el) {
    expect(el.querySelector('span').text).toEqual('test')
    done()
  })
})

polymer.with(el1, el2, ..., callback)

Creates elements, runs callback and removes all elements after it

This function is very similar to create except it removes all created elements after callback is finished:

it('should be true', function(done) {
  polymer.with('<x-el><span>test</span></x-el>', function(el) {
    expect(el.querySelector('span').text).toEqual('test')
    done()
  })
})

polymer.clear()

Removes all created elements. Usefull for teardown:

afterEach(function(done) {
  polymer.clear()
})

polymer.first, polymer.last, polymer.elements

Returns first, last or all created and existed elements respectively. Usefull with beforeEach blocks:

beforeEach(function(done) {
  polymer.create('my-first-element', 'my-second-element', done)
})

it('should be true', function() {
  expect(polymer.first.tagName).toEqual('MY-FIRST-ELEMENT')
  expect(polymer.last.tagName).toEqual('MY-SECOND-ELEMENT')
  expect(polymer.elements.length).toEqual(2)
  expect(polymer.elements[0].tagName).toEqual('MY-FIRST-ELEMENT')
})