Что такое Page Object

Описание Page Objects
var LoginPage = function() {
this.userName = element(by.input('login.userName'));
this.password = element(by.input('login.password'));
this.loginButton = element(by.css('Button[ng-click^="login"]'));
this.logoutButton = element(by.css('Button[ng-click^="logout"]'));
this.registerButton = element(by.css('Button[ng-click^="register"]'));
this.greeting = element(by.binding("Welcome, {{currentBrewer.FirstName}}"));
this.gravatarImage = element(by.tagName('img'));
};
module.exports = new LoginPage();