Spectron

Easily test your Electron apps using ChromeDriver and WebdriverIO.

This minor version of this library tracks the minor version of the Electron versions released. So if you are using Electron 1.0.x you would want to use a spectron dependency of ~3.0.0 in your package.json file.

Learn more from this presentation.

🚨 Upgrading from 1.x to 2.x/3.x? Read the changelog.

Using

npm install --save-dev spectron

Spectron works with any testing framework but the following example uses mocha:

var Application = require('spectron').Application
var assert = require('assert')

describe('application launch', function () {
  this.timeout(10000)

  beforeEach(function () {
    this.app = new Application({
      path: '/Applications/MyApp.app/Contents/MacOS/MyApp'
    })
    return this.app.start()
  })

  afterEach(function () {
    if (this.app && this.app.isRunning()) {
      return this.app.stop()
    }
  })

  it('shows an initial window', function () {
    return this.app.client.getWindowCount().then(function (count) {
      assert.equal(count, 1)
    })
  })
})

Application API

Spectron exports an Application class that when configured, can start and stop your Electron application.

new Application(options)

Create a new application with the following options:

path - String path to the application executable to launch. Required
args - Array of arguments to pass to the executable. See here for details on the Chrome arguments.
cwd- String path to the working directory to use for the launched application. Defaults to process.cwd().
env - Object of additional environment variables to set in the launched application.
host - String host name of the launched chromedriver process. Defaults to 'localhost'.
port - Number port of the launched chromedriver process. Defaults to 9515.
nodePath - String path to a node executable to launch ChromeDriver with. Defaults to process.execPath.
connectionRetryCount - Number of retry attempts to make when connecting to ChromeDriver. Defaults to 10 attempts.
connectionRetryTimeout - Number in milliseconds to wait for connections to ChromeDriver to be made. Defaults to 30000 milliseconds.
quitTimeout - Number in milliseconds to wait for application quitting. Defaults to 1000 milliseconds.
requireName - Custom property name to use when requiring modules. Defaults to require. This should only be used if your application deletes the main window.require function and assigns it to another property name on window.
startTimeout - Number in milliseconds to wait for ChromeDriver to start. Defaults to 5000 milliseconds.
waitTimeout - Number in milliseconds to wait for calls like waitUntilTextExists and waitUntilWindowLoaded to complete. Defaults to 5000 milliseconds.
debuggerAddress - String address of a Chrome debugger server to connect to.
chromeDriverLogPath - String path to file to store ChromeDriver logs in. Setting this option enables --verbose logging when starting ChromeDriver.

Node Integration

The Electron helpers provided by Spectron require accessing the core Electron APIs in the renderer processes of your application. So if your Electron application has nodeIntegration set to false then you'll need to expose a require window global to Spectron so it can access the core Electron APIs.

You can do this by adding a preload script that does the following:

if (process.env.NODE_ENV === 'test') {
  window.electronRequire = require
}

Then create the Spectron Application with the requireName option set to 'electronRequire' and then runs your tests via NODE_ENV=test npm test.

Note: This is only required if you tests are accessing any Electron APIs. You don't need to do this if you are only accessing the helpers on the client property which do not require Node integration.

Properties

client

Spectron uses WebdriverIO and exposes the managed client property on the created Application instances.

The full client API provided by WebdriverIO can be found here.

Several additional commands are provided specific to Electron.

All the commands return a Promise.

So if you wanted to get the text of an element you would do:

app.client.getText('#error-alert').then(function (errorText) {
  console.log('The #error-alert text content is ' + errorText)
})

electron

The electron property is your gateway to accessing the full Electron API.

Each Electron module is exposed as a property on the electron property so you can think of it as an alias for require('electron') from within your app.

So if you wanted to access the clipboard API in your tests you would do:

app.electron.clipboard.writeText('pasta')
   .electron.clipboard.readText().then(function (clipboardText) {
     console.log('The clipboard text is ' + clipboardText)
   })

browserWindow

The browserWindow property is an alias for require('electron').remote.getCurrentWindow().

It provides you access to the current BrowserWindow and contains all the APIs.

So if you wanted to check if the current window is visible in your tests you would do:

app.browserWindow.isVisible().then(function (visible) {
  console.log('window is visible? ' + visible)
})

It is named browserWindow instead of window so that it doesn't collide with the WebDriver command of that name.

capturePage

The async capturePage API is supported but instead of taking a callback it returns a Promise that resolves to a Buffer that is the image data of screenshot.

app.browserWindow.capturePage().then(function (imageBuffer) {
  fs.writeFile('page.png', imageBuffer)
})

webContents

The webContents property is an alias for require('electron').remote.getCurrentWebContents().

It provides you access to the WebContents for the current window and contains all the APIs.

So if you wanted to check if the current window is loading in your tests you would do:

app.webContents.isLoading().then(function (visible) {
  console.log('window is loading? ' + visible)
})

savePage

The async savePage API is supported but instead of taking a callback it returns a Promise that will raise any errors and resolve to undefined when complete.

app.webContents.savePage('/Users/kevin/page.html', 'HTMLComplete')
  .then(function () {
    console.log('page saved')
  }).catch(function (error) {
    console.error('saving page failed', error.message)
  })

mainProcess

The mainProcess property is an alias for require('electron').remote.process.

It provides you access to the main process's process global.

So if you wanted to get the argv for the main process in your tests you would do:

app.mainProcess.argv().then(function (argv) {
  console.log('main process args: ' + argv)
})

Properties on the process are exposed as functions that return promises so make sure to call mainProcess.env().then(...) instead of mainProcess.env.then(...).

rendererProcess

The rendererProcess property is an alias for global.process.

It provides you access to the renderer process's process global.

So if you wanted to get the environment variables for the renderer process in your tests you would do:

app.rendererProcess.env().then(function (env) {
  console.log('main process args: ' + env)
})

Methods

start()

Starts the application. Returns a Promise that will be resolved when the application is ready to use. You should always wait for start to complete before running any commands.

stop()

Stops the application. Returns a Promise that will be resolved once the application has stopped.

restart()

Stops the application and then starts it. Returns a Promise that will be resolved once the application has started again.

client.getMainProcessLogs()

Gets the console log output from the main process. The logs are cleared after they are returned.

Returns a Promise that resolves to an array of string log messages

app.client.getMainProcessLogs().then(function (logs) {
  logs.forEach(function (log) {
    console.log(log)
  })
})

client.getRenderProcessLogs()

Gets the console log output from the render process. The logs are cleared after they are returned.

Returns a Promise that resolves to an array of log objects.

app.client.getRenderProcessLogs().then(function (logs) {
  logs.forEach(function (log) {
    console.log(log.message)
    console.log(log.source)
    console.log(log.level)
  })
})

client.getSelectedText()

Get the selected text in the current window.

app.client.getSelectedText().then(function (selectedText) {
  console.log(selectedText)
})

client.getWindowCount()

Gets the number of open windows.

app.client.getWindowCount().then(function (count) {
  console.log(count)
})

client.waitUntilTextExists(selector, text, [timeout])

Waits until the element matching the given selector contains the given text. Takes an optional timeout in milliseconds that defaults to 5000.

app.client.waitUntilTextExists('#message', 'Success', 10000)

client.waitUntilWindowLoaded([timeout])

Wait until the window is no longer loading. Takes an optional timeout in milliseconds that defaults to 5000.

app.client.waitUntilWindowLoaded(10000)

client.windowByIndex(index)

Focus a window using its index from the windowHandles() array.

app.client.windowByIndex(1)

Continuous Integration

On Travis CI

You will want to add the following to your .travis.yml file when building on Linux:

before_script:
  - "export DISPLAY=:99.0"
  - "sh -e /etc/init.d/xvfb start"
  - sleep 3 # give xvfb some time to start

Check out Spectron's .travis.yml file for a production example.

On AppVeyor

You will want to add the following to your appveyor.yml file:

os: unstable

Check out Spectron's appveyor.yml file for a production example.

Test Library Examples

With Chai As Promised

WebdriverIO is promise-based and so it pairs really well with the Chai as Promised library that builds on top of Chai.

Using these together allows you to chain assertions together and have fewer callback blocks. See below for a simple example:

npm install --save-dev chai
npm install --save-dev chai-as-promised

var Application = require('spectron').Application
var chai = require('chai')
var chaiAsPromised = require('chai-as-promised')
var path = require('path')

chai.should()
chai.use(chaiAsPromised)

describe('application launch', function () {
  beforeEach(function () {
    this.app = new Application({
      path: '/Applications/MyApp.app/Contents/MacOS/MyApp'
    })
    return this.app.start()
  })

  beforeEach(function () {
    chaiAsPromised.transferPromiseness = this.app.transferPromiseness
  })

  afterEach(function () {
    if (this.app && this.app.isRunning()) {
      return this.app.stop()
    }
  })

  it('opens a window', function () {
    return this.app.client.waitUntilWindowLoaded()
      .getWindowCount().should.eventually.equal(1)
      .browserWindow.isMinimized().should.eventually.be.false
      .browserWindow.isDevToolsOpened().should.eventually.be.false
      .browserWindow.isVisible().should.eventually.be.true
      .browserWindow.isFocused().should.eventually.be.true
      .browserWindow.getBounds().should.eventually.have.property('width').and.be.above(0)
      .browserWindow.getBounds().should.eventually.have.property('height').and.be.above(0)
  })
})

With AVA

Spectron works with AVA, which allows you to write your tests in ES2015+ without doing any extra work.

import test from 'ava';
import {Application} from 'spectron';

test.beforeEach(t => {
  t.context.app = new Application({
    path: '/Applications/MyApp.app/Contents/MacOS/MyApp'
  });

  return t.context.app.start();
});

test.afterEach(t => {
  return t.context.app.stop();
});

test(t => {
  return t.context.app.client.waitUntilWindowLoaded()
    .getWindowCount().then(count => {
      t.is(count, 1);
    }).browserWindow.isMinimized().then(min => {
      t.false(min);
    }).browserWindow.isDevToolsOpened().then(opened => {
      t.false(opened);
    }).browserWindow.isVisible().then(visible => {
      t.true(visible);
    }).browserWindow.isFocused().then(focused => {
      t.true(focused);
    }).browserWindow.getBounds().then(bounds => {
      t.true(bounds.width > 0);
      t.true(bounds.height > 0);
    });
});

AVA has built-in support for async functions, which simplifies async operations:

import test from 'ava';
import {Application} from 'spectron';

test.beforeEach(async t => {
  t.context.app = new Application({
    path: '/Applications/MyApp.app/Contents/MacOS/MyApp'
  });

  await t.context.app.start();
});

test.afterEach.always(async t => {
  await t.context.app.stop();
});

test(async t => {
  const app = t.context.app;
  await app.client.waitUntilWindowLoaded();

  const win = app.browserWindow;
  t.is(await app.client.getWindowCount(), 1);
  t.false(await win.isMinimized());
  t.false(await win.isDevToolsOpened());
  t.true(await win.isVisible());
  t.true(await win.isFocused());

  const {width, height} = await win.getBounds();
  t.true(width > 0);
  t.true(height > 0);
});

yuya-oc/spectron