electron/spec/api-desktop-capturer-spec.js

const assert = require('assert')
const {desktopCapturer, remote, screen} = require('electron')

const isCI = remote.getGlobal('isCi')

describe('desktopCapturer', () => {
  before(function () {
    if (isCI && process.platform === 'win32') {
      this.skip()
    }
  })

  it('should return a non-empty array of sources', (done) => {
    desktopCapturer.getSources({
      types: ['window', 'screen']
    }, (error, sources) => {
      assert.equal(error, null)
      assert.notEqual(sources.length, 0)
      done()
    })
  })

  it('throws an error for invalid options', (done) => {
    desktopCapturer.getSources(['window', 'screen'], (error) => {
      assert.equal(error.message, 'Invalid options')
      done()
    })
  })

  it('does not throw an error when called more than once (regression)', (done) => {
    let callCount = 0
    const callback = (error, sources) => {
      callCount++
      assert.equal(error, null)
      assert.notEqual(sources.length, 0)
      if (callCount === 2) done()
    }

    desktopCapturer.getSources({types: ['window', 'screen']}, callback)
    desktopCapturer.getSources({types: ['window', 'screen']}, callback)
  })

  it('responds to subsequent calls of different options', (done) => {
    let callCount = 0
    const callback = (error, sources) => {
      callCount++
      assert.equal(error, null)
      if (callCount === 2) done()
    }

    desktopCapturer.getSources({types: ['window']}, callback)
    desktopCapturer.getSources({types: ['screen']}, callback)
  })

  it('returns an empty display_id for window sources on Windows and Mac', (done) => {
    // Linux doesn't return any window sources.
    if (process.platform !== 'win32' && process.platform !== 'darwin') {
      return done()
    }
    desktopCapturer.getSources({types: ['window']}, (error, sources) => {
      assert.equal(error, null)
      assert.notEqual(sources.length, 0)
      sources.forEach((source) => { assert.equal(source.display_id.length, 0) })
      done()
    })
  })

  it('returns display_ids matching the Screen API on Windows and Mac', (done) => {
    if (process.platform !== 'win32' && process.platform !== 'darwin') {
      return done()
    }
    const displays = screen.getAllDisplays()
    desktopCapturer.getSources({types: ['screen']}, (error, sources) => {
      assert.equal(error, null)
      assert.notEqual(sources.length, 0)
      assert.equal(sources.length, displays.length)
      for (let i = 0; i < sources.length; i++) {
        assert.equal(sources[i].display_id, displays[i].id)
      }
      done()
    })
  })
})