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

const assert = require('assert');
const desktopCapturer = require('electron').desktopCapturer;

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

  it('does not throw an error when called more than once (regression)', function(done) {
    var callCount = 0;
    var callback = function (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);
  })
});