electron/spec/api-browser-window-spec.js

'use strict'

const assert = require('assert')
const fs = require('fs')
const path = require('path')
const os = require('os')
const qs = require('querystring')
const http = require('http')
const {closeWindow} = require('./window-helpers')

const {ipcRenderer, remote, screen} = require('electron')
const {app, ipcMain, BrowserWindow, protocol} = remote

const isCI = remote.getGlobal('isCi')

describe('browser-window module', function () {
  var fixtures = path.resolve(__dirname, 'fixtures')
  var w = null
  var server, postData

  before(function (done) {
    const filePath = path.join(fixtures, 'pages', 'a.html')
    const fileStats = fs.statSync(filePath)
    postData = [
      {
        type: 'rawData',
        bytes: new Buffer('username=test&file=')
      },
      {
        type: 'file',
        filePath: filePath,
        offset: 0,
        length: fileStats.size,
        modificationTime: fileStats.mtime.getTime() / 1000
      }
    ]
    server = http.createServer(function (req, res) {
      function respond () {
        if (req.method === 'POST') {
          let body = ''
          req.on('data', (data) => {
            if (data) {
              body += data
            }
          })
          req.on('end', () => {
            let parsedData = qs.parse(body)
            fs.readFile(filePath, (err, data) => {
              if (err) return
              if (parsedData.username === 'test' &&
                  parsedData.file === data.toString()) {
                res.end()
              }
            })
          })
        } else {
          res.end()
        }
      }
      setTimeout(respond, req.url.includes('slow') ? 200 : 0)
    })
    server.listen(0, '127.0.0.1', function () {
      server.url = 'http://127.0.0.1:' + server.address().port
      done()
    })
  })

  after(function () {
    server.close()
    server = null
  })

  beforeEach(function () {
    w = new BrowserWindow({
      show: false,
      width: 400,
      height: 400,
      webPreferences: {
        backgroundThrottling: false
      }
    })
  })

  afterEach(function () {
    return closeWindow(w).then(function () { w = null })
  })

  describe('BrowserWindow.close()', function () {
    it('should emit unload handler', function (done) {
      w.webContents.on('did-finish-load', function () {
        w.close()
      })
      w.once('closed', function () {
        var test = path.join(fixtures, 'api', 'unload')
        var content = fs.readFileSync(test)
        fs.unlinkSync(test)
        assert.equal(String(content), 'unload')
        done()
      })
      w.loadURL('file://' + path.join(fixtures, 'api', 'unload.html'))
    })

    it('should emit beforeunload handler', function (done) {
      w.once('onbeforeunload', function () {
        done()
      })
      w.webContents.on('did-finish-load', function () {
        w.close()
      })
      w.loadURL('file://' + path.join(fixtures, 'api', 'beforeunload-false.html'))
    })
  })

  describe('window.close()', function () {
    it('should emit unload handler', function (done) {
      w.once('closed', function () {
        var test = path.join(fixtures, 'api', 'close')
        var content = fs.readFileSync(test)
        fs.unlinkSync(test)
        assert.equal(String(content), 'close')
        done()
      })
      w.loadURL('file://' + path.join(fixtures, 'api', 'close.html'))
    })

    it('should emit beforeunload handler', function (done) {
      w.once('onbeforeunload', function () {
        done()
      })
      w.loadURL('file://' + path.join(fixtures, 'api', 'close-beforeunload-false.html'))
    })
  })

  describe('BrowserWindow.destroy()', function () {
    it('prevents users to access methods of webContents', function () {
      var webContents = w.webContents
      w.destroy()
      assert.throws(function () {
        webContents.getId()
      }, /Object has been destroyed/)
    })
  })

  describe('BrowserWindow.loadURL(url)', function () {
    it('should emit did-start-loading event', function (done) {
      w.webContents.on('did-start-loading', function () {
        done()
      })
      w.loadURL('about:blank')
    })

    it('should emit ready-to-show event', function (done) {
      w.on('ready-to-show', function () {
        done()
      })
      w.loadURL('about:blank')
    })

    it('should emit did-get-response-details event', function (done) {
      // expected {fileName: resourceType} pairs
      var expectedResources = {
        'did-get-response-details.html': 'mainFrame',
        'logo.png': 'image'
      }
      var responses = 0
      w.webContents.on('did-get-response-details', function (event, status, newUrl, oldUrl, responseCode, method, referrer, headers, resourceType) {
        responses++
        var fileName = newUrl.slice(newUrl.lastIndexOf('/') + 1)
        var expectedType = expectedResources[fileName]
        assert(!!expectedType, `Unexpected response details for ${newUrl}`)
        assert(typeof status === 'boolean', 'status should be boolean')
        assert.equal(responseCode, 200)
        assert.equal(method, 'GET')
        assert(typeof referrer === 'string', 'referrer should be string')
        assert(!!headers, 'headers should be present')
        assert(typeof headers === 'object', 'headers should be object')
        assert.equal(resourceType, expectedType, 'Incorrect resourceType')
        if (responses === Object.keys(expectedResources).length) {
          done()
        }
      })
      w.loadURL('file://' + path.join(fixtures, 'pages', 'did-get-response-details.html'))
    })

    it('should emit did-fail-load event for files that do not exist', function (done) {
      w.webContents.on('did-fail-load', function (event, code, desc, url, isMainFrame) {
        assert.equal(code, -6)
        assert.equal(desc, 'ERR_FILE_NOT_FOUND')
        assert.equal(isMainFrame, true)
        done()
      })
      w.loadURL('file://a.txt')
    })

    it('should emit did-fail-load event for invalid URL', function (done) {
      w.webContents.on('did-fail-load', function (event, code, desc, url, isMainFrame) {
        assert.equal(desc, 'ERR_INVALID_URL')
        assert.equal(code, -300)
        assert.equal(isMainFrame, true)
        done()
      })
      w.loadURL('http://example:port')
    })

    it('should set `mainFrame = false` on did-fail-load events in iframes', function (done) {
      w.webContents.on('did-fail-load', function (event, code, desc, url, isMainFrame) {
        assert.equal(isMainFrame, false)
        done()
      })
      w.loadURL('file://' + path.join(fixtures, 'api', 'did-fail-load-iframe.html'))
    })

    it('does not crash in did-fail-provisional-load handler', function (done) {
      w.webContents.once('did-fail-provisional-load', function () {
        w.loadURL('http://127.0.0.1:11111')
        done()
      })
      w.loadURL('http://127.0.0.1:11111')
    })

    describe('POST navigations', function () {
      afterEach(() => {
        w.webContents.session.webRequest.onBeforeSendHeaders(null)
      })

      it('supports specifying POST data', function (done) {
        w.webContents.on('did-finish-load', () => done())
        w.loadURL(server.url, {postData: postData})
      })

      it('sets the content type header on URL encoded forms', function (done) {
        w.webContents.on('did-finish-load', () => {
          w.webContents.session.webRequest.onBeforeSendHeaders((details, callback) => {
            assert.equal(details.requestHeaders['content-type'], 'application/x-www-form-urlencoded')
            done()
          })
          w.webContents.executeJavaScript(`
            form = document.createElement('form')
            form.method = 'POST'
            form.target = '_blank'
            form.submit()
          `)
        })
        w.loadURL(server.url)
      })

      it('sets the content type header on multi part forms', function (done) {
        w.webContents.on('did-finish-load', () => {
          w.webContents.session.webRequest.onBeforeSendHeaders((details, callback) => {
            assert(details.requestHeaders['content-type'].startsWith('multipart/form-data; boundary=----WebKitFormBoundary'))
            done()
          })
          w.webContents.executeJavaScript(`
            form = document.createElement('form')
            form.method = 'POST'
            form.target = '_blank'
            form.enctype = 'multipart/form-data'
            file = document.createElement('input')
            file.type = 'file'
            file.name = 'file'
            form.appendChild(file)
            form.submit()
          `)
        })
        w.loadURL(server.url)
      })
    })
  })

  describe('BrowserWindow.show()', function () {
    if (isCI) {
      return
    }

    it('should focus on window', function () {
      w.show()
      assert(w.isFocused())
    })

    it('should make the window visible', function () {
      w.show()
      assert(w.isVisible())
    })

    it('emits when window is shown', function (done) {
      w.once('show', function () {
        assert.equal(w.isVisible(), true)
        done()
      })
      w.show()
    })
  })

  describe('BrowserWindow.hide()', function () {
    if (isCI) {
      return
    }

    it('should defocus on window', function () {
      w.hide()
      assert(!w.isFocused())
    })

    it('should make the window not visible', function () {
      w.show()
      w.hide()
      assert(!w.isVisible())
    })

    it('emits when window is hidden', function (done) {
      w.show()
      w.once('hide', function () {
        assert.equal(w.isVisible(), false)
        done()
      })
      w.hide()
    })
  })

  describe('BrowserWindow.showInactive()', function () {
    it('should not focus on window', function () {
      w.showInactive()
      assert(!w.isFocused())
    })
  })

  describe('BrowserWindow.focus()', function () {
    it('does not make the window become visible', function () {
      assert.equal(w.isVisible(), false)
      w.focus()
      assert.equal(w.isVisible(), false)
    })
  })

  describe('BrowserWindow.blur()', function () {
    it('removes focus from window', function () {
      w.blur()
      assert(!w.isFocused())
    })
  })

  describe('BrowserWindow.capturePage(rect, callback)', function () {
    it('calls the callback with a Buffer', function (done) {
      w.capturePage({
        x: 0,
        y: 0,
        width: 100,
        height: 100
      }, function (image) {
        assert.equal(image.isEmpty(), true)
        done()
      })
    })
  })

  describe('BrowserWindow.setSize(width, height)', function () {
    it('sets the window size', function (done) {
      var size = [300, 400]
      w.once('resize', function () {
        assertBoundsEqual(w.getSize(), size)
        done()
      })
      w.setSize(size[0], size[1])
    })
  })

  describe('BrowserWindow.setMinimum/MaximumSize(width, height)', function () {
    it('sets the maximum and minimum size of the window', function () {
      assert.deepEqual(w.getMinimumSize(), [0, 0])
      assert.deepEqual(w.getMaximumSize(), [0, 0])

      w.setMinimumSize(100, 100)
      assertBoundsEqual(w.getMinimumSize(), [100, 100])
      assertBoundsEqual(w.getMaximumSize(), [0, 0])

      w.setMaximumSize(900, 600)
      assertBoundsEqual(w.getMinimumSize(), [100, 100])
      assertBoundsEqual(w.getMaximumSize(), [900, 600])
    })
  })

  describe('BrowserWindow.setAspectRatio(ratio)', function () {
    it('resets the behaviour when passing in 0', function (done) {
      var size = [300, 400]
      w.setAspectRatio(1 / 2)
      w.setAspectRatio(0)
      w.once('resize', function () {
        assertBoundsEqual(w.getSize(), size)
        done()
      })
      w.setSize(size[0], size[1])
    })
  })

  describe('BrowserWindow.setPosition(x, y)', function () {
    it('sets the window position', function (done) {
      var pos = [10, 10]
      w.once('move', function () {
        var newPos = w.getPosition()
        assert.equal(newPos[0], pos[0])
        assert.equal(newPos[1], pos[1])
        done()
      })
      w.setPosition(pos[0], pos[1])
    })
  })

  describe('BrowserWindow.setContentSize(width, height)', function () {
    it('sets the content size', function () {
      var size = [400, 400]
      w.setContentSize(size[0], size[1])
      var after = w.getContentSize()
      assert.equal(after[0], size[0])
      assert.equal(after[1], size[1])
    })

    it('works for a frameless window', function () {
      w.destroy()
      w = new BrowserWindow({
        show: false,
        frame: false,
        width: 400,
        height: 400
      })
      var size = [400, 400]
      w.setContentSize(size[0], size[1])
      var after = w.getContentSize()
      assert.equal(after[0], size[0])
      assert.equal(after[1], size[1])
    })
  })

  describe('BrowserWindow.setContentBounds(bounds)', function () {
    it('sets the content size and position', function (done) {
      var bounds = {x: 10, y: 10, width: 250, height: 250}
      w.once('resize', function () {
        assertBoundsEqual(w.getContentBounds(), bounds)
        done()
      })
      w.setContentBounds(bounds)
    })

    it('works for a frameless window', function (done) {
      w.destroy()
      w = new BrowserWindow({
        show: false,
        frame: false,
        width: 300,
        height: 300
      })
      var bounds = {x: 10, y: 10, width: 250, height: 250}
      w.once('resize', function () {
        assert.deepEqual(w.getContentBounds(), bounds)
        done()
      })
      w.setContentBounds(bounds)
    })
  })

  describe('BrowserWindow.setProgressBar(progress)', function () {
    it('sets the progress', function () {
      assert.doesNotThrow(function () {
        if (process.platform === 'darwin') {
          app.dock.setIcon(path.join(fixtures, 'assets', 'logo.png'))
        }
        w.setProgressBar(0.5)

        if (process.platform === 'darwin') {
          app.dock.setIcon(null)
        }
        w.setProgressBar(-1)
      })
    })

    it('sets the progress using "paused" mode', function () {
      assert.doesNotThrow(function () {
        w.setProgressBar(0.5, {mode: 'paused'})
      })
    })

    it('sets the progress using "error" mode', function () {
      assert.doesNotThrow(function () {
        w.setProgressBar(0.5, {mode: 'error'})
      })
    })

    it('sets the progress using "normal" mode', function () {
      assert.doesNotThrow(function () {
        w.setProgressBar(0.5, {mode: 'normal'})
      })
    })
  })

  describe('BrowserWindow.setAlwaysOnTop(flag, level)', function () {
    it('sets the window as always on top', function () {
      assert.equal(w.isAlwaysOnTop(), false)
      w.setAlwaysOnTop(true, 'dock')
      assert.equal(w.isAlwaysOnTop(), true)
      w.setAlwaysOnTop(false)
      assert.equal(w.isAlwaysOnTop(), false)
      w.setAlwaysOnTop(true)
      assert.equal(w.isAlwaysOnTop(), true)
    })
  })

  describe('BrowserWindow.setAutoHideCursor(autoHide)', () => {
    if (process.platform !== 'darwin') {
      it('is not available on non-macOS platforms', () => {
        assert.ok(!w.setAutoHideCursor)
      })

      return
    }

    it('allows changing cursor auto-hiding', () => {
      assert.doesNotThrow(() => {
        w.setAutoHideCursor(false)
        w.setAutoHideCursor(true)
      })
    })
  })

  describe('BrowserWindow.setVibrancy(type)', function () {
    it('allows setting, changing, and removing the vibrancy', function () {
      assert.doesNotThrow(function () {
        w.setVibrancy('light')
        w.setVibrancy('dark')
        w.setVibrancy(null)
        w.setVibrancy('ultra-dark')
        w.setVibrancy('')
      })
    })
  })

  describe('BrowserWindow.setAppDetails(options)', function () {
    it('supports setting the app details', function () {
      if (process.platform !== 'win32') return

      const iconPath = path.join(fixtures, 'assets', 'icon.ico')

      assert.doesNotThrow(function () {
        w.setAppDetails({appId: 'my.app.id'})
        w.setAppDetails({appIconPath: iconPath, appIconIndex: 0})
        w.setAppDetails({appIconPath: iconPath})
        w.setAppDetails({relaunchCommand: 'my-app.exe arg1 arg2', relaunchDisplayName: 'My app name'})
        w.setAppDetails({relaunchCommand: 'my-app.exe arg1 arg2'})
        w.setAppDetails({relaunchDisplayName: 'My app name'})
        w.setAppDetails({
          appId: 'my.app.id',
          appIconPath: iconPath,
          appIconIndex: 0,
          relaunchCommand: 'my-app.exe arg1 arg2',
          relaunchDisplayName: 'My app name'
        })
        w.setAppDetails({})
      })

      assert.throws(function () {
        w.setAppDetails()
      }, /Insufficient number of arguments\./)
    })
  })

  describe('BrowserWindow.fromId(id)', function () {
    it('returns the window with id', function () {
      assert.equal(w.id, BrowserWindow.fromId(w.id).id)
    })
  })

  describe('"useContentSize" option', function () {
    it('make window created with content size when used', function () {
      w.destroy()
      w = new BrowserWindow({
        show: false,
        width: 400,
        height: 400,
        useContentSize: true
      })
      var contentSize = w.getContentSize()
      assert.equal(contentSize[0], 400)
      assert.equal(contentSize[1], 400)
    })

    it('make window created with window size when not used', function () {
      var size = w.getSize()
      assert.equal(size[0], 400)
      assert.equal(size[1], 400)
    })

    it('works for a frameless window', function () {
      w.destroy()
      w = new BrowserWindow({
        show: false,
        frame: false,
        width: 400,
        height: 400,
        useContentSize: true
      })
      var contentSize = w.getContentSize()
      assert.equal(contentSize[0], 400)
      assert.equal(contentSize[1], 400)
      var size = w.getSize()
      assert.equal(size[0], 400)
      assert.equal(size[1], 400)
    })
  })

  describe('"title-bar-style" option', function () {
    if (process.platform !== 'darwin') {
      return
    }
    if (parseInt(os.release().split('.')[0]) < 14) {
      return
    }

    it('creates browser window with hidden title bar', function () {
      w.destroy()
      w = new BrowserWindow({
        show: false,
        width: 400,
        height: 400,
        titleBarStyle: 'hidden'
      })
      var contentSize = w.getContentSize()
      assert.equal(contentSize[1], 400)
    })

    it('creates browser window with hidden inset title bar', function () {
      w.destroy()
      w = new BrowserWindow({
        show: false,
        width: 400,
        height: 400,
        titleBarStyle: 'hidden-inset'
      })
      var contentSize = w.getContentSize()
      assert.equal(contentSize[1], 400)
    })
  })

  describe('enableLargerThanScreen" option', function () {
    if (process.platform === 'linux') {
      return
    }

    beforeEach(function () {
      w.destroy()
      w = new BrowserWindow({
        show: true,
        width: 400,
        height: 400,
        enableLargerThanScreen: true
      })
    })

    it('can move the window out of screen', function () {
      w.setPosition(-10, -10)
      var after = w.getPosition()
      assert.equal(after[0], -10)
      assert.equal(after[1], -10)
    })

    it('can set the window larger than screen', function () {
      var size = screen.getPrimaryDisplay().size
      size.width += 100
      size.height += 100
      w.setSize(size.width, size.height)
      assertBoundsEqual(w.getSize(), [size.width, size.height])
    })
  })

  describe('"zoomToPageWidth" option', function () {
    it('sets the window width to the page width when used', function () {
      if (process.platform !== 'darwin') return

      w.destroy()
      w = new BrowserWindow({
        show: false,
        width: 500,
        height: 400,
        zoomToPageWidth: true
      })
      w.maximize()
      assert.equal(w.getSize()[0], 500)
    })
  })

  describe('"web-preferences" option', function () {
    afterEach(function () {
      ipcMain.removeAllListeners('answer')
    })

    describe('"preload" option', function () {
      it('loads the script before other scripts in window', function (done) {
        var preload = path.join(fixtures, 'module', 'set-global.js')
        ipcMain.once('answer', function (event, test) {
          assert.equal(test, 'preload')
          done()
        })
        w.destroy()
        w = new BrowserWindow({
          show: false,
          webPreferences: {
            preload: preload
          }
        })
        w.loadURL('file://' + path.join(fixtures, 'api', 'preload.html'))
      })

      it('can successfully delete the Buffer global', function (done) {
        var preload = path.join(fixtures, 'module', 'delete-buffer.js')
        ipcMain.once('answer', function (event, test) {
          assert.equal(test.toString(), 'buffer')
          done()
        })
        w.destroy()
        w = new BrowserWindow({
          show: false,
          webPreferences: {
            preload: preload
          }
        })
        w.loadURL('file://' + path.join(fixtures, 'api', 'preload.html'))
      })
    })

    describe('"node-integration" option', function () {
      it('disables node integration when specified to false', function (done) {
        var preload = path.join(fixtures, 'module', 'send-later.js')
        ipcMain.once('answer', function (event, test) {
          assert.equal(test, 'undefined')
          done()
        })
        w.destroy()
        w = new BrowserWindow({
          show: false,
          webPreferences: {
            preload: preload,
            nodeIntegration: false
          }
        })
        w.loadURL('file://' + path.join(fixtures, 'api', 'blank.html'))
      })
    })

    describe('"sandbox" option', function () {
      function waitForEvents (emitter, events, callback) {
        let count = events.length
        for (let event of events) {
          emitter.once(event, () => {
            if (!--count) callback()
          })
        }
      }

      const preload = path.join(fixtures, 'module', 'preload-sandbox.js')

      // http protocol to simulate accessing another domain. This is required
      // because the code paths for cross domain popups is different.
      function crossDomainHandler (request, callback) {
        callback({
          mimeType: 'text/html',
          data: `<html><body><h1>${request.url}</h1></body></html>`
        })
      }

      before(function (done) {
        protocol.interceptStringProtocol('http', crossDomainHandler, function () {
          done()
        })
      })

      after(function (done) {
        protocol.uninterceptProtocol('http', function () {
          done()
        })
      })

      it('exposes ipcRenderer to preload script', function (done) {
        ipcMain.once('answer', function (event, test) {
          assert.equal(test, 'preload')
          done()
        })
        w.destroy()
        w = new BrowserWindow({
          show: false,
          webPreferences: {
            sandbox: true,
            preload: preload
          }
        })
        w.loadURL('file://' + path.join(fixtures, 'api', 'preload.html'))
      })

      it('exposes "exit" event to preload script', function (done) {
        w.destroy()
        w = new BrowserWindow({
          show: false,
          webPreferences: {
            sandbox: true,
            preload: preload
          }
        })
        let htmlPath = path.join(fixtures, 'api', 'sandbox.html?exit-event')
        const pageUrl = 'file://' + htmlPath
        w.loadURL(pageUrl)
        ipcMain.once('answer', function (event, url) {
          let expectedUrl = pageUrl
          if (process.platform === 'win32') {
            expectedUrl = 'file:///' + htmlPath.replace(/\\/g, '/')
          }
          assert.equal(url, expectedUrl)
          done()
        })
      })

      it('should open windows in same domain with cross-scripting enabled', function (done) {
        w.destroy()
        w = new BrowserWindow({
          show: false,
          webPreferences: {
            sandbox: true,
            preload: preload
          }
        })
        let htmlPath = path.join(fixtures, 'api', 'sandbox.html?window-open')
        const pageUrl = 'file://' + htmlPath
        w.loadURL(pageUrl)
        w.webContents.once('new-window', (e, url, frameName, disposition, options) => {
          let expectedUrl = pageUrl
          if (process.platform === 'win32') {
            expectedUrl = 'file:///' + htmlPath.replace(/\\/g, '/')
          }
          assert.equal(url, expectedUrl)
          assert.equal(frameName, 'popup!')
          assert.equal(options.x, 50)
          assert.equal(options.y, 60)
          assert.equal(options.width, 500)
          assert.equal(options.height, 600)
          ipcMain.once('answer', function (event, html) {
            assert.equal(html, '<h1>scripting from opener</h1>')
            done()
          })
        })
      })

      it('should open windows in another domain with cross-scripting disabled', function (done) {
        w.destroy()
        w = new BrowserWindow({
          show: false,
          webPreferences: {
            sandbox: true,
            preload: preload
          }
        })
        let htmlPath = path.join(fixtures, 'api', 'sandbox.html?window-open-external')
        const pageUrl = 'file://' + htmlPath
        let popupWindow
        w.loadURL(pageUrl)
        w.webContents.once('new-window', (e, url, frameName, disposition, options) => {
          assert.equal(url, 'http://www.google.com/#q=electron')
          assert.equal(options.x, 55)
          assert.equal(options.y, 65)
          assert.equal(options.width, 505)
          assert.equal(options.height, 605)
          ipcMain.once('child-loaded', function (event, openerIsNull, html) {
            assert(openerIsNull)
            assert.equal(html, '<h1>http://www.google.com/#q=electron</h1>')
            ipcMain.once('answer', function (event, exceptionMessage) {
              assert(/Blocked a frame with origin/.test(exceptionMessage))

              // FIXME this popup window should be closed in sandbox.html
              closeWindow(popupWindow, {assertSingleWindow: false}).then(() => {
                popupWindow = null
                done()
              })
            })
            w.webContents.send('child-loaded')
          })
        })

        app.once('browser-window-created', function (event, window) {
          popupWindow = window
        })
      })

      it('should set ipc event sender correctly', function (done) {
        w.destroy()
        w = new BrowserWindow({
          show: false,
          webPreferences: {
            sandbox: true,
            preload: preload
          }
        })
        let htmlPath = path.join(fixtures, 'api', 'sandbox.html?verify-ipc-sender')
        const pageUrl = 'file://' + htmlPath
        w.loadURL(pageUrl)
        w.webContents.once('new-window', (e, url, frameName, disposition, options) => {
          let parentWc = w.webContents
          let childWc = options.webContents
          assert.notEqual(parentWc, childWc)
          ipcMain.once('parent-ready', function (event) {
            assert.equal(parentWc, event.sender)
            parentWc.send('verified')
          })
          ipcMain.once('child-ready', function (event) {
            assert.equal(childWc, event.sender)
            childWc.send('verified')
          })
          waitForEvents(ipcMain, [
            'parent-answer',
            'child-answer'
          ], done)
        })
      })

      describe('event handling', function () {
        it('works for window events', function (done) {
          waitForEvents(w, [
            'page-title-updated'
          ], done)
          w.loadURL('file://' + path.join(fixtures, 'api', 'sandbox.html?window-events'))
        })

        it('works for web contents events', function (done) {
          waitForEvents(w.webContents, [
            'did-navigate',
            'did-fail-load',
            'did-stop-loading'
          ], done)
          w.loadURL('file://' + path.join(fixtures, 'api', 'sandbox.html?webcontents-stop'))
          waitForEvents(w.webContents, [
            'did-finish-load',
            'did-frame-finish-load',
            'did-navigate-in-page',
            'will-navigate',
            'did-start-loading',
            'did-stop-loading',
            'did-frame-finish-load',
            'dom-ready'
          ], done)
          w.loadURL('file://' + path.join(fixtures, 'api', 'sandbox.html?webcontents-events'))
        })
      })
    })
  })

  describe('beforeunload handler', function () {
    it('returning undefined would not prevent close', function (done) {
      w.once('closed', function () {
        done()
      })
      w.loadURL('file://' + path.join(fixtures, 'api', 'close-beforeunload-undefined.html'))
    })

    it('returning false would prevent close', function (done) {
      w.once('onbeforeunload', function () {
        done()
      })
      w.loadURL('file://' + path.join(fixtures, 'api', 'close-beforeunload-false.html'))
    })

    it('returning empty string would prevent close', function (done) {
      w.once('onbeforeunload', function () {
        done()
      })
      w.loadURL('file://' + path.join(fixtures, 'api', 'close-beforeunload-empty-string.html'))
    })
  })

  describe('new-window event', function () {
    if (isCI && process.platform === 'darwin') {
      return
    }

    it('emits when window.open is called', function (done) {
      w.webContents.once('new-window', function (e, url, frameName, disposition, options, additionalFeatures) {
        e.preventDefault()
        assert.equal(url, 'http://host/')
        assert.equal(frameName, 'host')
        assert.equal(additionalFeatures[0], 'this-is-not-a-standard-feature')
        done()
      })
      w.loadURL('file://' + fixtures + '/pages/window-open.html')
    })

    it('emits when window.open is called with no webPreferences', function (done) {
      w.destroy()
      w = new BrowserWindow({ show: false })
      w.webContents.once('new-window', function (e, url, frameName, disposition, options, additionalFeatures) {
        e.preventDefault()
        assert.equal(url, 'http://host/')
        assert.equal(frameName, 'host')
        assert.equal(additionalFeatures[0], 'this-is-not-a-standard-feature')
        done()
      })
      w.loadURL('file://' + fixtures + '/pages/window-open.html')
    })

    it('emits when link with target is called', function (done) {
      w.webContents.once('new-window', function (e, url, frameName) {
        e.preventDefault()
        assert.equal(url, 'http://host/')
        assert.equal(frameName, 'target')
        done()
      })
      w.loadURL('file://' + fixtures + '/pages/target-name.html')
    })
  })

  describe('maximize event', function () {
    if (isCI) {
      return
    }

    it('emits when window is maximized', function (done) {
      w.once('maximize', function () {
        done()
      })
      w.show()
      w.maximize()
    })
  })

  describe('unmaximize event', function () {
    if (isCI) {
      return
    }

    it('emits when window is unmaximized', function (done) {
      w.once('unmaximize', function () {
        done()
      })
      w.show()
      w.maximize()
      w.unmaximize()
    })
  })

  describe('minimize event', function () {
    if (isCI) {
      return
    }

    it('emits when window is minimized', function (done) {
      w.once('minimize', function () {
        done()
      })
      w.show()
      w.minimize()
    })
  })

  describe('beginFrameSubscription method', function () {
    // This test is too slow, only test it on CI.
    if (!isCI) return

    it('subscribes to frame updates', function (done) {
      let called = false
      w.loadURL('file://' + fixtures + '/api/frame-subscriber.html')
      w.webContents.on('dom-ready', function () {
        w.webContents.beginFrameSubscription(function (data) {
          // This callback might be called twice.
          if (called) return
          called = true

          assert.notEqual(data.length, 0)
          w.webContents.endFrameSubscription()
          done()
        })
      })
    })

    it('subscribes to frame updates (only dirty rectangle)', function (done) {
      let called = false
      w.loadURL('file://' + fixtures + '/api/frame-subscriber.html')
      w.webContents.on('dom-ready', function () {
        w.webContents.beginFrameSubscription(true, function (data) {
          // This callback might be called twice.
          if (called) return
          called = true

          assert.notEqual(data.length, 0)
          w.webContents.endFrameSubscription()
          done()
        })
      })
    })

    it('throws error when subscriber is not well defined', function (done) {
      w.loadURL('file://' + fixtures + '/api/frame-subscriber.html')
      try {
        w.webContents.beginFrameSubscription(true, true)
      } catch (e) {
        done()
      }
    })
  })

  describe('savePage method', function () {
    const savePageDir = path.join(fixtures, 'save_page')
    const savePageHtmlPath = path.join(savePageDir, 'save_page.html')
    const savePageJsPath = path.join(savePageDir, 'save_page_files', 'test.js')
    const savePageCssPath = path.join(savePageDir, 'save_page_files', 'test.css')

    after(function () {
      try {
        fs.unlinkSync(savePageCssPath)
        fs.unlinkSync(savePageJsPath)
        fs.unlinkSync(savePageHtmlPath)
        fs.rmdirSync(path.join(savePageDir, 'save_page_files'))
        fs.rmdirSync(savePageDir)
      } catch (e) {
        // Ignore error
      }
    })

    it('should save page to disk', function (done) {
      w.webContents.on('did-finish-load', function () {
        w.webContents.savePage(savePageHtmlPath, 'HTMLComplete', function (error) {
          assert.equal(error, null)
          assert(fs.existsSync(savePageHtmlPath))
          assert(fs.existsSync(savePageJsPath))
          assert(fs.existsSync(savePageCssPath))
          done()
        })
      })
      w.loadURL('file://' + fixtures + '/pages/save_page/index.html')
    })
  })

  describe('BrowserWindow options argument is optional', function () {
    it('should create a window with default size (800x600)', function () {
      w.destroy()
      w = new BrowserWindow()
      var size = w.getSize()
      assert.equal(size[0], 800)
      assert.equal(size[1], 600)
    })
  })

  describe('window states', function () {
    it('does not resize frameless windows when states change', function () {
      w.destroy()
      w = new BrowserWindow({
        frame: false,
        width: 300,
        height: 200,
        show: false
      })

      w.setMinimizable(false)
      w.setMinimizable(true)
      assert.deepEqual(w.getSize(), [300, 200])

      w.setResizable(false)
      w.setResizable(true)
      assert.deepEqual(w.getSize(), [300, 200])

      w.setMaximizable(false)
      w.setMaximizable(true)
      assert.deepEqual(w.getSize(), [300, 200])

      w.setFullScreenable(false)
      w.setFullScreenable(true)
      assert.deepEqual(w.getSize(), [300, 200])

      w.setClosable(false)
      w.setClosable(true)
      assert.deepEqual(w.getSize(), [300, 200])
    })

    describe('resizable state', function () {
      it('can be changed with resizable option', function () {
        w.destroy()
        w = new BrowserWindow({show: false, resizable: false})
        assert.equal(w.isResizable(), false)

        if (process.platform === 'darwin') {
          assert.equal(w.isMaximizable(), true)
        }
      })

      it('can be changed with setResizable method', function () {
        assert.equal(w.isResizable(), true)
        w.setResizable(false)
        assert.equal(w.isResizable(), false)
        w.setResizable(true)
        assert.equal(w.isResizable(), true)
      })
    })

    describe('loading main frame state', function () {
      it('is true when the main frame is loading', function (done) {
        w.webContents.on('did-start-loading', function () {
          assert.equal(w.webContents.isLoadingMainFrame(), true)
          done()
        })
        w.webContents.loadURL(server.url)
      })

      it('is false when only a subframe is loading', function (done) {
        w.webContents.once('did-finish-load', function () {
          assert.equal(w.webContents.isLoadingMainFrame(), false)
          w.webContents.on('did-start-loading', function () {
            assert.equal(w.webContents.isLoadingMainFrame(), false)
            done()
          })
          w.webContents.executeJavaScript(`
            var iframe = document.createElement('iframe')
            iframe.src = '${server.url}/page2'
            document.body.appendChild(iframe)
          `)
        })
        w.webContents.loadURL(server.url)
      })

      it('is true when navigating to pages from the same origin', function (done) {
        w.webContents.once('did-finish-load', function () {
          assert.equal(w.webContents.isLoadingMainFrame(), false)
          w.webContents.on('did-start-loading', function () {
            assert.equal(w.webContents.isLoadingMainFrame(), true)
            done()
          })
          w.webContents.loadURL(`${server.url}/page2`)
        })
        w.webContents.loadURL(server.url)
      })
    })
  })

  describe('window states (excluding Linux)', function () {
    // Not implemented on Linux.
    if (process.platform === 'linux') return

    describe('movable state', function () {
      it('can be changed with movable option', function () {
        w.destroy()
        w = new BrowserWindow({show: false, movable: false})
        assert.equal(w.isMovable(), false)
      })

      it('can be changed with setMovable method', function () {
        assert.equal(w.isMovable(), true)
        w.setMovable(false)
        assert.equal(w.isMovable(), false)
        w.setMovable(true)
        assert.equal(w.isMovable(), true)
      })
    })

    describe('minimizable state', function () {
      it('can be changed with minimizable option', function () {
        w.destroy()
        w = new BrowserWindow({show: false, minimizable: false})
        assert.equal(w.isMinimizable(), false)
      })

      it('can be changed with setMinimizable method', function () {
        assert.equal(w.isMinimizable(), true)
        w.setMinimizable(false)
        assert.equal(w.isMinimizable(), false)
        w.setMinimizable(true)
        assert.equal(w.isMinimizable(), true)
      })
    })

    describe('maximizable state', function () {
      it('can be changed with maximizable option', function () {
        w.destroy()
        w = new BrowserWindow({show: false, maximizable: false})
        assert.equal(w.isMaximizable(), false)
      })

      it('can be changed with setMaximizable method', function () {
        assert.equal(w.isMaximizable(), true)
        w.setMaximizable(false)
        assert.equal(w.isMaximizable(), false)
        w.setMaximizable(true)
        assert.equal(w.isMaximizable(), true)
      })

      it('is not affected when changing other states', function () {
        w.setMaximizable(false)
        assert.equal(w.isMaximizable(), false)
        w.setMinimizable(false)
        assert.equal(w.isMaximizable(), false)
        w.setClosable(false)
        assert.equal(w.isMaximizable(), false)

        w.setMaximizable(true)
        assert.equal(w.isMaximizable(), true)
        w.setClosable(true)
        assert.equal(w.isMaximizable(), true)
        w.setFullScreenable(false)
        assert.equal(w.isMaximizable(), true)
        w.setResizable(false)
        assert.equal(w.isMaximizable(), true)
      })
    })

    describe('fullscreenable state', function () {
      // Only implemented on macOS.
      if (process.platform !== 'darwin') return

      it('can be changed with fullscreenable option', function () {
        w.destroy()
        w = new BrowserWindow({show: false, fullscreenable: false})
        assert.equal(w.isFullScreenable(), false)
      })

      it('can be changed with setFullScreenable method', function () {
        assert.equal(w.isFullScreenable(), true)
        w.setFullScreenable(false)
        assert.equal(w.isFullScreenable(), false)
        w.setFullScreenable(true)
        assert.equal(w.isFullScreenable(), true)
      })
    })

    describe('closable state', function () {
      it('can be changed with closable option', function () {
        w.destroy()
        w = new BrowserWindow({show: false, closable: false})
        assert.equal(w.isClosable(), false)
      })

      it('can be changed with setClosable method', function () {
        assert.equal(w.isClosable(), true)
        w.setClosable(false)
        assert.equal(w.isClosable(), false)
        w.setClosable(true)
        assert.equal(w.isClosable(), true)
      })
    })

    describe('hasShadow state', function () {
      // On Window there is no shadow by default and it can not be changed
      // dynamically.
      it('can be changed with hasShadow option', function () {
        w.destroy()
        let hasShadow = process.platform !== 'darwin'
        w = new BrowserWindow({show: false, hasShadow: hasShadow})
        assert.equal(w.hasShadow(), hasShadow)
      })

      it('can be changed with setHasShadow method', function () {
        if (process.platform !== 'darwin') return

        assert.equal(w.hasShadow(), true)
        w.setHasShadow(false)
        assert.equal(w.hasShadow(), false)
        w.setHasShadow(true)
        assert.equal(w.hasShadow(), true)
      })
    })
  })

  describe('BrowserWindow.restore()', function () {
    it('should restore the previous window size', function () {
      if (w != null) w.destroy()

      w = new BrowserWindow({
        minWidth: 800,
        width: 800
      })

      const initialSize = w.getSize()
      w.minimize()
      w.restore()
      assertBoundsEqual(w.getSize(), initialSize)
    })
  })

  describe('BrowserWindow.unmaximize()', function () {
    it('should restore the previous window position', function () {
      if (w != null) w.destroy()
      w = new BrowserWindow()

      const initialPosition = w.getPosition()
      w.maximize()
      w.unmaximize()
      assertBoundsEqual(w.getPosition(), initialPosition)
    })
  })

  describe('parent window', function () {
    let c = null

    beforeEach(function () {
      if (c != null) c.destroy()
      c = new BrowserWindow({show: false, parent: w})
    })

    afterEach(function () {
      if (c != null) c.destroy()
      c = null
    })

    describe('parent option', function () {
      it('sets parent window', function () {
        assert.equal(c.getParentWindow(), w)
      })

      it('adds window to child windows of parent', function () {
        assert.deepEqual(w.getChildWindows(), [c])
      })

      it('removes from child windows of parent when window is closed', function (done) {
        c.once('closed', () => {
          assert.deepEqual(w.getChildWindows(), [])
          done()
        })
        c.close()
      })
    })

    describe('win.setParentWindow(parent)', function () {
      if (process.platform === 'win32') return

      beforeEach(function () {
        if (c != null) c.destroy()
        c = new BrowserWindow({show: false})
      })

      it('sets parent window', function () {
        assert.equal(w.getParentWindow(), null)
        assert.equal(c.getParentWindow(), null)
        c.setParentWindow(w)
        assert.equal(c.getParentWindow(), w)
        c.setParentWindow(null)
        assert.equal(c.getParentWindow(), null)
      })

      it('adds window to child windows of parent', function () {
        assert.deepEqual(w.getChildWindows(), [])
        c.setParentWindow(w)
        assert.deepEqual(w.getChildWindows(), [c])
        c.setParentWindow(null)
        assert.deepEqual(w.getChildWindows(), [])
      })

      it('removes from child windows of parent when window is closed', function (done) {
        c.once('closed', () => {
          assert.deepEqual(w.getChildWindows(), [])
          done()
        })
        c.setParentWindow(w)
        c.close()
      })
    })

    describe('modal option', function () {
      // The isEnabled API is not reliable on macOS.
      if (process.platform === 'darwin') return

      beforeEach(function () {
        if (c != null) c.destroy()
        c = new BrowserWindow({show: false, parent: w, modal: true})
      })

      it('disables parent window', function () {
        assert.equal(w.isEnabled(), true)
        c.show()
        assert.equal(w.isEnabled(), false)
      })

      it('enables parent window when closed', function (done) {
        c.once('closed', () => {
          assert.equal(w.isEnabled(), true)
          done()
        })
        c.show()
        c.close()
      })

      it('disables parent window recursively', function () {
        let c2 = new BrowserWindow({show: false, parent: w, modal: true})
        c.show()
        assert.equal(w.isEnabled(), false)
        c2.show()
        assert.equal(w.isEnabled(), false)
        c.destroy()
        assert.equal(w.isEnabled(), false)
        c2.destroy()
        assert.equal(w.isEnabled(), true)
      })
    })
  })

  describe('window.webContents.send(channel, args...)', function () {
    it('throws an error when the channel is missing', function () {
      assert.throws(function () {
        w.webContents.send()
      }, 'Missing required channel argument')

      assert.throws(function () {
        w.webContents.send(null)
      }, 'Missing required channel argument')
    })
  })

  describe('dev tool extensions', function () {
    describe('BrowserWindow.addDevToolsExtension', function () {
      let showPanelIntervalId

      beforeEach(function () {
        BrowserWindow.removeDevToolsExtension('foo')
        assert.equal(BrowserWindow.getDevToolsExtensions().hasOwnProperty('foo'), false)

        var extensionPath = path.join(__dirname, 'fixtures', 'devtools-extensions', 'foo')
        BrowserWindow.addDevToolsExtension(extensionPath)
        assert.equal(BrowserWindow.getDevToolsExtensions().hasOwnProperty('foo'), true)

        w.webContents.on('devtools-opened', function () {
          showPanelIntervalId = setInterval(function () {
            if (w && w.devToolsWebContents) {
              var showLastPanel = function () {
                var lastPanelId = WebInspector.inspectorView._tabbedPane._tabs.peekLast().id
                WebInspector.inspectorView.showPanel(lastPanelId)
              }
              w.devToolsWebContents.executeJavaScript(`(${showLastPanel})()`)
            } else {
              clearInterval(showPanelIntervalId)
            }
          }, 100)
        })

        w.loadURL('about:blank')
      })

      afterEach(function () {
        clearInterval(showPanelIntervalId)
      })

      it('throws errors for missing manifest.json files', function () {
        assert.throws(function () {
          BrowserWindow.addDevToolsExtension(path.join(__dirname, 'does-not-exist'))
        }, /ENOENT: no such file or directory/)
      })

      it('throws errors for invalid manifest.json files', function () {
        assert.throws(function () {
          BrowserWindow.addDevToolsExtension(path.join(__dirname, 'fixtures', 'devtools-extensions', 'bad-manifest'))
        }, /Unexpected token }/)
      })

      describe('when the devtools is docked', function () {
        it('creates the extension', function (done) {
          w.webContents.openDevTools({mode: 'bottom'})

          ipcMain.once('answer', function (event, message) {
            assert.equal(message.runtimeId, 'foo')
            assert.equal(message.tabId, w.webContents.id)
            assert.equal(message.i18nString, 'foo - bar (baz)')
            assert.deepEqual(message.storageItems, {
              local: {
                set: {hello: 'world', world: 'hello'},
                remove: {world: 'hello'},
                clear: {}
              },
              sync: {
                set: {foo: 'bar', bar: 'foo'},
                remove: {foo: 'bar'},
                clear: {}
              }
            })
            done()
          })
        })
      })

      describe('when the devtools is undocked', function () {
        it('creates the extension', function (done) {
          w.webContents.openDevTools({mode: 'undocked'})

          ipcMain.once('answer', function (event, message, extensionId) {
            assert.equal(message.runtimeId, 'foo')
            assert.equal(message.tabId, w.webContents.id)
            done()
          })
        })
      })
    })

    it('works when used with partitions', function (done) {
      if (w != null) {
        w.destroy()
      }
      w = new BrowserWindow({
        show: false,
        webPreferences: {
          partition: 'temp'
        }
      })

      var extensionPath = path.join(__dirname, 'fixtures', 'devtools-extensions', 'foo')
      BrowserWindow.removeDevToolsExtension('foo')
      BrowserWindow.addDevToolsExtension(extensionPath)

      let showPanelIntervalId = null

      w.webContents.once('devtools-opened', function () {
        showPanelIntervalId = setInterval(function () {
          if (w && w.devToolsWebContents) {
            var showLastPanel = function () {
              var lastPanelId = WebInspector.inspectorView._tabbedPane._tabs.peekLast().id
              WebInspector.inspectorView.showPanel(lastPanelId)
            }
            w.devToolsWebContents.executeJavaScript(`(${showLastPanel})()`)
          } else {
            clearInterval(showPanelIntervalId)
          }
        }, 100)
      })

      w.loadURL('about:blank')
      w.webContents.openDevTools({mode: 'bottom'})

      ipcMain.once('answer', function (event, message) {
        assert.equal(message.runtimeId, 'foo')
        clearInterval(showPanelIntervalId)
        done()
      })
    })

    it('serializes the registered extensions on quit', function () {
      var extensionName = 'foo'
      var extensionPath = path.join(__dirname, 'fixtures', 'devtools-extensions', extensionName)
      var serializedPath = path.join(app.getPath('userData'), 'DevTools Extensions')

      BrowserWindow.addDevToolsExtension(extensionPath)
      app.emit('will-quit')
      assert.deepEqual(JSON.parse(fs.readFileSync(serializedPath)), [extensionPath])

      BrowserWindow.removeDevToolsExtension(extensionName)
      app.emit('will-quit')
      assert.equal(fs.existsSync(serializedPath), false)
    })
  })

  describe('window.webContents.executeJavaScript', function () {
    var expected = 'hello, world!'
    var expectedErrorMsg = 'woops!'
    var code = `(() => "${expected}")()`
    var asyncCode = `(() => new Promise(r => setTimeout(() => r("${expected}"), 500)))()`
    var badAsyncCode = `(() => new Promise((r, e) => setTimeout(() => e("${expectedErrorMsg}"), 500)))()`

    it('doesnt throw when no calback is provided', function () {
      const result = ipcRenderer.sendSync('executeJavaScript', code, false)
      assert.equal(result, 'success')
    })

    it('returns result when calback is provided', function (done) {
      ipcRenderer.send('executeJavaScript', code, true)
      ipcRenderer.once('executeJavaScript-response', function (event, result) {
        assert.equal(result, expected)
        done()
      })
    })

    it('returns result if the code returns an asyncronous promise', function (done) {
      ipcRenderer.send('executeJavaScript', asyncCode, true)
      ipcRenderer.once('executeJavaScript-response', function (event, result) {
        assert.equal(result, expected)
        done()
      })
    })

    it('resolves the returned promise with the result', function (done) {
      ipcRenderer.send('executeJavaScript', code, true)
      ipcRenderer.once('executeJavaScript-promise-response', function (event, result) {
        assert.equal(result, expected)
        done()
      })
    })

    it('resolves the returned promise with the result if the code returns an asyncronous promise', function (done) {
      ipcRenderer.send('executeJavaScript', asyncCode, true)
      ipcRenderer.once('executeJavaScript-promise-response', function (event, result) {
        assert.equal(result, expected)
        done()
      })
    })

    it('rejects the returned promise if an async error is thrown', function (done) {
      ipcRenderer.send('executeJavaScript', badAsyncCode, true)
      ipcRenderer.once('executeJavaScript-promise-error', function (event, error) {
        assert.equal(error, expectedErrorMsg)
        done()
      })
    })

    it('works after page load and during subframe load', function (done) {
      w.webContents.once('did-finish-load', function () {
        // initiate a sub-frame load, then try and execute script during it
        w.webContents.executeJavaScript(`
          var iframe = document.createElement('iframe')
          iframe.src = '${server.url}/slow'
          document.body.appendChild(iframe)
        `, function () {
          w.webContents.executeJavaScript('console.log(\'hello\')', function () {
            done()
          })
        })
      })
      w.loadURL(server.url)
    })

    it('executes after page load', function (done) {
      w.webContents.executeJavaScript(code, function (result) {
        assert.equal(result, expected)
        done()
      })
      w.loadURL(server.url)
    })

    it('works with result objects that have DOM class prototypes', function (done) {
      w.webContents.executeJavaScript('document.location', function (result) {
        assert.equal(result.origin, server.url)
        assert.equal(result.protocol, 'http:')
        done()
      })
      w.loadURL(server.url)
    })
  })

  describe('previewFile', function () {
    it('opens the path in Quick Look on macOS', function () {
      if (process.platform !== 'darwin') return

      assert.doesNotThrow(function () {
        w.previewFile(__filename)
        w.closeFilePreview()
      })
    })
  })

  describe('offscreen rendering', function () {
    beforeEach(function () {
      if (w != null) w.destroy()
      w = new BrowserWindow({
        show: false,
        webPreferences: {
          backgroundThrottling: false,
          offscreen: true
        }
      })
    })

    it('creates offscreen window', function (done) {
      w.webContents.once('paint', function (event, rect, data, size) {
        assert.notEqual(data.length, 0)
        done()
      })
      w.loadURL('file://' + fixtures + '/api/offscreen-rendering.html')
    })

    describe('window.webContents.isOffscreen()', function () {
      it('is true for offscreen type', function () {
        w.loadURL('file://' + fixtures + '/api/offscreen-rendering.html')
        assert.equal(w.webContents.isOffscreen(), true)
      })

      it('is false for regular window', function () {
        let c = new BrowserWindow({show: false})
        assert.equal(c.webContents.isOffscreen(), false)
        c.destroy()
      })
    })

    describe('window.webContents.isPainting()', function () {
      it('returns whether is currently painting', function (done) {
        w.webContents.once('paint', function (event, rect, data, size) {
          assert.equal(w.webContents.isPainting(), true)
          done()
        })
        w.loadURL('file://' + fixtures + '/api/offscreen-rendering.html')
      })
    })

    describe('window.webContents.stopPainting()', function () {
      it('stops painting', function (done) {
        w.webContents.on('dom-ready', function () {
          w.webContents.stopPainting()
          assert.equal(w.webContents.isPainting(), false)
          done()
        })
        w.loadURL('file://' + fixtures + '/api/offscreen-rendering.html')
      })
    })

    describe('window.webContents.startPainting()', function () {
      it('starts painting', function (done) {
        w.webContents.on('dom-ready', function () {
          w.webContents.stopPainting()
          w.webContents.startPainting()
          w.webContents.once('paint', function (event, rect, data, size) {
            assert.equal(w.webContents.isPainting(), true)
            done()
          })
        })
        w.loadURL('file://' + fixtures + '/api/offscreen-rendering.html')
      })
    })

    describe('window.webContents.getFrameRate()', function () {
      it('has default frame rate', function (done) {
        w.webContents.once('paint', function (event, rect, data, size) {
          assert.equal(w.webContents.getFrameRate(), 60)
          done()
        })
        w.loadURL('file://' + fixtures + '/api/offscreen-rendering.html')
      })
    })

    describe('window.webContents.setFrameRate(frameRate)', function () {
      it('sets custom frame rate', function (done) {
        w.webContents.on('dom-ready', function () {
          w.webContents.setFrameRate(30)
          w.webContents.once('paint', function (event, rect, data, size) {
            assert.equal(w.webContents.getFrameRate(), 30)
            done()
          })
        })
        w.loadURL('file://' + fixtures + '/api/offscreen-rendering.html')
      })
    })
  })
})

const assertBoundsEqual = (actual, expect) => {
  if (!isScaleFactorRounding()) {
    assert.deepEqual(expect, actual)
  } else if (Array.isArray(actual)) {
    assertWithinDelta(actual[0], expect[0], 1, 'x')
    assertWithinDelta(actual[1], expect[1], 1, 'y')
  } else {
    assertWithinDelta(actual.x, expect.x, 1, 'x')
    assertWithinDelta(actual.y, expect.y, 1, 'y')
    assertWithinDelta(actual.width, expect.width, 1, 'width')
    assertWithinDelta(actual.height, expect.height, 1, 'height')
  }
}

const assertWithinDelta = (actual, expect, delta, label) => {
  const result = Math.abs(actual - expect)
  assert.ok(result <= delta, `${label} value of ${expect} was not within ${delta} of ${actual}`)
}

// Is the display's scale factor possibly causing rounding of pixel coordinate
// values?
const isScaleFactorRounding = () => {
  const {scaleFactor} = screen.getPrimaryDisplay()
  // Return true if scale factor is non-integer value
  if (Math.round(scaleFactor) !== scaleFactor) return true
  // Return true if scale factor is odd number above 2
  return scaleFactor > 2 && scaleFactor % 2 === 1
}