How to Handle Modal Dialog Box in Selenium WebDriver Java

TestPopups.java

package test;


import java.util.set;
import java.util.Iterator;


import org.openqa.selenium.*;
import org.openqa.selenium.support.ui.ExpectedConditions;
import org.testng.Assert;
import org.testng.annotations.Test;


public class TestPopups extends BaseTest
{
   @Test(description = "test to verify popups")
   public void verifyPopups() throws InterruptedException
   {
       //navigate to the website
       System.out.println("Navigating to the website");
       driver.get("https://www.lambdatest.com/selenium-playground/window-popup-modal-demo");


       //fetch and save the handle of current window
       System.out.println("storing the main window handle");
       String mainWindowHandle = driver.getWindowHandle();


       //click the button to get a popup (new tab in this case)
       System.out.println("Clicking launch popup button");
       WebElement followButtonOnMainWindow = driver.findElement(By.xpath("//a[contains(@title,'Twitter')]"));
       followButtonOnMainWindow.click();


       //get the list of all window handles after the new tab
       //should have length 2 since 1 new tab opens up
       System.out.println("Fetching the list of all window handles and asserting them");
       Set<String> windowHandles = driver.getWindowHandles();
       Assert.assertEquals(windowHandles.size(), 2, "Verify the total number of handles");


       //switch to new opened tab
       System.out.println("Switching to the new window handle");
       Iterator<String> itr = windowHandles.iterator();
       while (itr.hasNext()) {
           String childWindowHandle = itr.next();
           // to skip the handle of our main window and switch to new one
           if (!mainWindowHandle.equalsIgnoreCase(childWindowHandle))
               driver.switchTo().window(childWindowHandle);
       }


       wait.until(ExpectedConditions.visibilityOfElementLocated(By.xpath("//span[text()='Follow']")));
      
       // to verify that driver focus is shifted to popup window
       System.out.println("Asserting some element on the new popup window to confirm switch");
       WebElement twitterFollowButton = driver.findElement(By.xpath("//span[text()='Follow']"));
       Assert.assertTrue(twitterFollowButton.isDisplayed(), "Verify twitter follow button is displayed");


       // shift driver back to main window and verify
       System.out.println("Switching back to main window and asserting same");
       driver.switchTo().window(mainWindowHandle);
       wait.until(ExpectedConditions.visibilityOfElementLocated(By.xpath("//a[contains(@title,'Twitter')]")));
       Assert.assertTrue(followButtonOnMainWindow.isDisplayed(), "Verify focus is shifted to main window");
   }
}