One of the key features of Selenium is support for running tests on a variety of web browsers available. You can develop a test on one browser and run it on all the supported browsers as needed. This feature is essential for cross-browser testing of your web application. You can run tests on combinations of operating systems and web browsers.

One of the key features of Selenium is its ability to locate different types of elements used on a page and the ability to interact with them. Selenium provides various ways or strategies to locate elements and perform actions such as clicking, typing text, selecting an option from the element, or performing verification on the state or property of the element, such as a text value. We can also check if the element is enabled or disabled, is checked or unchecked.

The following table describes some of the important locator strategies that you can use with IDE or WebDriver API:

In addition to the aforementioned strategies, Selenium WebDriver supports the following strategies:

Selenium provides an extensive support for the standard HTML elements used on a web page. You can interact with the HTML elements by using built-in commands and APIs for building simple to complex tests. The following table shows some key commands and API methods for interacting with a page and its elements:

Selenium WebDriver provides the WebElement class for interacting with HTML elements.

When Selenium scripts are played back, the application may not always respond with the same speed, especially for applications using AJAX. For example, it might take a few seconds for the following:

You can handle these anticipated timing problems by synchronizing your script to ensure that Selenium waits until your application is ready before performing a certain step. There are several options that you can use to synchronize your script using Selenium IDE and Selenium WebDriver.

The Page Object pattern provides tests for an interface, where a test can operate on the logical functionality offered by the page in a manner similar to the user accessing the page, but by hiding its internals. For example, if we build a Page Object for a login page that will provide a method to log in by accepting the username and password, and will take the user to the home page of the application. The test need not worry about what type of input controls are used for the login page, their locator details, navigation, and so on.

Tests should use objects of a page at a high level, where any change in layout or attributes used for the fields in the underlying page should not break the test.

Selenium WebDriver provides outstanding support for implementing the Page Object pattern via its PageFactory class. The Page Object pattern brings the following advantages for your tests:

The login page class provides an interface to the login page of the application to the tests as shown in the following diagram:

Here is Page Object for the login page of the test application.

The login page class contains locator details for the key elements needed for user login functionality. Elements from the login page are defined as private members of the LoginPage class. The test code will not have access to these elements. The LoginPage class provides a public login() method to the tests. The test needs to pass the e-mail address and password for a registered user to this method. The constructor of the LoginPage class uses the PageFactory.initElements() method to initialize WebElements defined in the class in the following way:

package demo.magentocommerce.pages;


import org.openqa.selenium.WebDriver;
import org.openqa.selenium.WebElement;
import org.openqa.selenium.support.FindBy;
import org.openqa.selenium.support.PageFactory;

public class Login {

  @FindBy(id="email")
  private WebElement emailField;

  @FindBy(id="pass")
  private WebElement passwordField;

  @FindBy(id="send2")
  private WebElement loginButton;

  public Login(WebDriver driver) {
    PageFactory.initElements(driver, this);
  }

  public void login(String email, String password) {
    emailField.sendKeys(email);
    passwordField.sendKeys(email);
    loginButton.click();
  }
}

Here is a sample test using the LoginPage class. The instance of the LoginPage class is created by passing the current driver instance. The login() method is called in the following way:

...
//Navigate to the Login Page
WebDriver driver = new FirefoxDriver();
driver.get("http://demo.magentocommerce.com/customer/account/login/");

//Create an instance of Login page and call the Login function 
LoginPage loginPage = new LoginPage(driver);
loginPage.login("[email protected]","xxxx");

//Verify the user is logged in
...