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An easy to use lightweight web testing framework for Node, designed for speed, maintainability and collaboration, now multi-browser. Bringing together everything you need out of the box - familiar BDD features/scenarios, a simple page object library, parallel testing and pretty rich reports, integrating Yadda 0.16.0, Selenium-Webdriver 2.48.2, Mocha 2.3.3 & Chai 3.4.1.



marvin-js was born as a clone of LateRooms' Moonraker.



It is possible to install marvin-js via npm - $ npm install marvin-js, or add marvin-js to your package.json.

Example project

You will find a full example project in the marvin-demo repository with everything you need to start using marvin-js - sample feature, step definitions, page objects and config in a suggested project structure.

The example tests use Chrome, so you will need the latest chromedriver downloaded and available on your path.

npm install then npm test from within the example directory to run the sample feature.


marvin-js is configured using a config.json file in your project root:

  "baseUrl": "",
  "featuresDir": "tests/features",
  "stepsDir": "tests/steps",
  "resultsDir": "results",
  "reporter": "marvin",
  "threads": 1,

  "tags": "@dev",

  "testTimeout": 60000,
  "elementTimeout": 5000,

  "browsers": [{
    "browserName": "chrome"
  }, {
    "seleniumServer": "",
    "browserName": "safari",
    "platform": "MAC"
  • baseUrl - Your base url, page object urls will be relative to this.*
  • featuresDir - The path to your features directory.*
  • stepsDir - The path to your step definitions directory.*
  • resultsDir - The path you'd like your results output to. *
  • reporter - The reporter type you'd like marvin-js to use (more on this below).
  • threads - The number of threads you'd like to run with. Note that Marvin will this number of threads for each browser. (default: 1)
  • tags - Optional: Comma seperated list of feature tags (more on this below).
  • testTimeout - The maximum test (scenario step) timeout before its marked as a fail (ms). (Default: 60000)
  • elementTimeout - The maximum time selenium will continuously try to find an element on the page (ms). (Default: 3000)
  • browsers - An array of objects, each one describing one browser's desired capabilities and optionally a seleniumServer address.*
  • language - Optional: sets the language to use (default: English).

* - Required.

Custom selenium servers

The example configuration above assumes using Chrome directly, and you're connecting to a different Selenium server only for one browser. You can use this to connect to cloud service providers like Saucelabs and Browserstack, even for only one browser. Please see below for example browser configurations.

You can also set which language to use, using language, if you intend to use non English feature & step definition files. A full list of supported languages is available here.

Run your tests

To start marvin-js run $ node node_modules/marvin-js/bin/marvin.js, or to make things easier you can add a shortcut in your package.json:

  "scripts": {
    "test": "node node_modules/marvin-js/bin/marvin"

... so you can simply run $ npm test. Note, you cannot pass command line args using the $ npm test shortcut.

Writing your tests

Tests for marvin-js are written using Yadda, a BDD implementation very similar to Cucumber and run using the Mocha JavaScript test framework.

Just like Cucumber, Yadda maps ordinary language steps to code, but can be quite flexible by not limiting you to a certain syntax (Given, When, Then) and allowing you to define your own...

Feature: Searching from the homepage

  Scenario: Simple Search

    Given I visit the home page
    When I search for 'Manchester'
    Whatever language I like here
exports.define = function (steps) {

  steps.given("I visit the home page", function () {
    // some code

  steps.when("I search for '$query'", function (query) {
    // some code

  steps.define("Whatever language I like here", function() {
    // some code


Although Yadda can support multiple libraries, marvin-js currently loads all step definitions found in your steps directory into one big shared library, just like Cucumber, so you have to be careful of step name clashes.


Components are exactly like page objects and allow you to group elements together into a component, then add that component itself to a page object.

// tests/pages/components/nav.js
var Component = require('marvin-js').Component

module.exports = new Component({

  selLanguage: { get: function () { return this.element('.locale select'); } },
  selCurrency: { get: function () { return this.element('.currency select'); } }

// tests/pages/home.js
var Page = require('marvin-js').Page,
    nav = require('./components/nav');

module.exports = new Page({

  url: { value: '/' },
  nav: { get: function () { return this.component(nav, "section[class='header']"); } },


Components are added to a page just like elements are but using: this.component(component, rootNode) where 'component' is your component object, and 'rootNode' is a css selector representing your components root node on the page.

All elements in your component are then scoped to this rootNode, so in the above example the element selLanguage with its .locale select selector is only found within the section[class='header'] element.

Your components can then be re-used across your page-objects and could appear in different places on the page.

Using your components:

// tests/steps/home-search-steps.js
var homePage = require('../pages/home');

exports.define = function (steps) {

  steps.given("I visit the home page", function () {

  steps.when("I select my currency", function () {;
    // etc..


Feature Tags

marvin-js supports feature tags to help keep things organized and allow you to selectively run certain features:

Feature: Searching from the homepage

  Scenario: Simple Search

    Given I visit the home page

In your config.json you can specify "tags": "@testing" to only run features with that tag or use '!@testing' to ignore those features. You can also use a comma seperated list - @accounts,@booking etc. Features tagged as @Pending will be skipped but included as pending features in the marvin-js test report.


The 'should' style of the Chai assertion library is available to use in your step definitions.

Saucelabs / Browserstack integration

To run your tests on cloud service providers like Saucelabs and Browserstack you just need to configure marvin-js with the correct seleniumServer address and browser capabilities that include your username/access key:


"browsers": [{
    "seleniumServer": "",
    "username": "{{YOUR_SAUCELABS_USERNAME}}",
    "accessKey": "{{YOUR_SAUCELABS_ACCESS_KEY}}",
    "browserName": "safari",
    "version": "8.0",
    "platform": "OS X 10.10"


"browsers": [{
    "seleniumServer": "",
    "browserstack.user": "{{YOUR_BROWSERSTACK_USERNAME}}",
    "browserstack.key": "{{YOUR_BROWSERSTACK_KEY}}",
    "browserName": "Safari",
    "browser_version": "8.0",
    "os": "OS X",
    "os_version": "Yosemite",
    "resolution": "1920x1080"

Note: As you can see in these examples each provider specifies capabilites differently so you will need to refer to your provider documentation:

Running your tests in parallel

marvin-js was designed with speed in mind and supports testing in parallel. To take advantage of this you can either:

  • add new browsers in the browsers config
  • increase the number of threads in the config

marvin-js will run all your browsers in parallel, with threads threads for each browser.

When you use more the one threads, marvin-js will split your feature files over the amount of threads set and starts a new child process (and browser) for each. If you have 4 feature files and want to use 2 threads, 2 features will be executed per thread / browser etc.

Parallel testing works as expected for remote driver connections just as it does locally. If you have powerful enough hardware to run your tests on and a large, high performing selenium grid instance to open connections to, you can dramatically reduce your test execution time.

At best, you will only be as quick as your longest running feature though, so if you have features with tons of scenarios in them you should think about breaking them down into smaller more manageable feature files.

Managing state

To share state between separate step libraries you can use Yadda's contexts.


As the tests are run using Mocha, you can use any of Mocha's reporters. Just set the required reporter in the config. As Mocha is designed to run serially though you will experience issues when running marvin-js in parallel, so marvin-js comes with its own custom reporter for Mocha.

marvin-js reporter

To use it set the reporter in your config to marvin. This reporter includes a Mocha spec-like console output and a html report saved to your results directory. The html report includes details of any errors and embedded browser screenshots.

Successful tests report Successful tests report

Successful tests with steps expanded Successful tests with steps expanded

Successful tests with steps and log values as table Successful tests with steps and log values as table

Successful tests with steps and log values as text Successful tests with steps and log values as text

Failed tests screen Failed tests report

Failed tests screen with steps expanded Failed tests with steps expanded

If you are using marvin-js in a non English language (set in the config) the report will try to find matching translations from this file, defaulting to English if any are missing. Please feel free to contribute any translations that you may require.

marvin-js reporter's

Session reference

marvin-js uses a session object to group functions related to the current test session and can be used in your step definitions etc:

var session = require('marvin-js').session;
session.resizeWindow(320, 480);
  • execute(fn) - Adds any function to webdriver's control flow. Please see control flows.
  • resizeWindow(x, y) - Resizes the browser window. By default its maximized.
  • refresh() - Refreshes the current page.
  • saveScreenshot(filename) - Saves a screenshot to /yourResultsDir/timestamp/screenshots/filename. This is called automatically on test failure.
  • deleteAllCookies() - Deletes all cookies.
  • addCookie(name, value, optDomain, optPath, optIsSecure, optExpiry) - Adds a cookie.
  • getCookie(name) - Gets a cookie by name.
  • getWebdriver() - Returns a reference to Webdriver that can be used, for instance, to create a new promise, e.g.
 var deferred = new session.getWebdriver().promise.Deferred();
  • getCurrentUrl() - Returns an url object, e.g:
Url {
    protocol: 'https:',
    slashes: true,
    auth: null,
    host: '',
    port: null,
    hostname: '',
    hash: null,
    search: null,
    query: null,
    pathname: '/mydir/mysubdir',
    ath: '/mydir/mysubdir',
    href: '' 

Done / planned development since we cloned Moonraker

  • updated all dependencies; simplified report's dependencies management; removed coffeescript (not a big fan, sorry)
  • refactoring directory tree
  • support Yadda's custom dictionary
  • store reports in different folders, so that a new test does not clear result's history; it is possible to enable the cleaning of the result folder via configuration, with "clean": true
  • POC logging from test steps in the report
  • POC not-blocking assertions
  • Support for simultaneous test run on multiple browsers and multiple selenium hubs
  • make possible to include screenshot into the report
  • refactoring feature-parser.js: it should not be in /utils
  • improve demo repository with more scenarios, like smartphone version scenarios and/or responsive design scenarios.
  • integrating selenium-webdriver until's module
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