electron/spec/fixtures/api/quit-app/main.js

var app = require('electron').app

app.on('ready', function () {
  // This setImmediate call gets the spec passing on Linux
  setImmediate(function () {
    app.exit(123)
  })
})

process.on('exit', function (code) {
  console.log('Exit event with code: ' + code)
})