I have come to know that Selenium is the father of UI testing.
Now my question is why then Angular team has developed Protractor. Can't the same job (that Protractor does) be done with Selenium for AngularJS based web applications?
Further, people are talking about Nightwatch.js too. So why there are so many E2E testing libraries/frameworks like Protracor or Nightwatch.
Protractor combines powerful tools and technologies such as NodeJS, Selenium, webDriver, Jasmine, Cucumber and Mocha. Has a bunch of customizations from Selenium to easily create tests for AngularJS applications. Speeds up your testing as it avoids the need for a lot of “sleeps” and “waits” in your tests, as it optimizes sleep and wait times. Allows tests to be organized based on Jasmine, thus allowing you to write both unit and functional tests on Jasmine. It runs on real browsers and headless browsers...
You can find all these information here => http://www.thoughtworks.com/insights/blog/testing-angularjs-apps-protractor.
Protractor also provides you to wait for scope changes using protractor.waitForAngular() which I think may or may not be implemented using Selenium. You'll still have to bang around your head in order simulate the same feature using selenium.
My opinion
If you just want to do UI testing and not interested in listening for scope changes or any angular specific events, you can go ahead with selenium. But it's a HUGE advantage using Protractor for e2e tests for Angular.
来源：https://stackoverflow.com/questions/26033901/use-of-selenium-for-angularjs-based-web-applications