End to End test with ionic 2

I am trying to perform tests in an ionic 2 application based on the question and the relevant links. I have gone through the referenced project and I have read the instructions. Unfortuantely, I could not run a test with protractor. I have in my package.json file:

"protractor": "^4.0.9",
"protractor-jasmine2-screenshot-reporter": "^0.3.2",

I need in my .spec.ts file to import:

import { ElementFinder, element, by } from 'protractor';

Otherwise element and by are not found.

I do not use any gulp file or typings since they are obsolete with ionic 2. The instructions refer to a tests order with conf.js file, which does not exist in the sample project (anymore?).

When I run the test with karma start I get diverse errors on selenium-webdriver or WebSocketServer.

What do I need in order to get the tests run with protractor?