Selenium WebDriver 4: The Complete Guide

<dependencies>
    <!-- Selenium Java Language Bindings (Selenium 4) -->
    <dependency>
        <groupId>org.seleniumhq.selenium</groupId>
        <artifactId>selenium-java</artifactId>
        <version>4.25.0</version>
    </dependency>

    <!-- TestNG Test Runner Framework -->
    <dependency>
        <groupId>org.testng</groupId>
        <artifactId>testng</artifactId>
        <version>7.10.2</version>
        <scope>test</scope>
    </dependency>

    <!-- SLF4J Simple Logger (Prevents framework logging warnings) -->
    <dependency>
        <groupId>org.slf4j</groupId>
        <artifactId>slf4j-simple</artifactId>
        <version>2.0.16</version>
        <scope>test</scope>
    </dependency>
</dependencies>

package com.testerrank.driver;

import org.openqa.selenium.WebDriver;
import org.openqa.selenium.chrome.ChromeDriver;
import org.openqa.selenium.chrome.ChromeOptions;
import java.time.Duration;

public class DriverFactory {

    public static WebDriver createChromeDriver(boolean isHeadless) {
        ChromeOptions options = new ChromeOptions();

        if (isHeadless) {
            // Chrome 109+ new headless mode: runs the full browser engine
            options.addArguments("--headless=new");
            // Mandatory for Docker/Linux environments to avoid /dev/shm OOM crashes
            options.addArguments("--disable-dev-shm-usage");
            options.addArguments("--no-sandbox");
            options.addArguments("--disable-gpu");
        }

        // Standardize viewport so tests do not fail on responsive layouts
        options.addArguments("--window-size=1920,1080");
        options.addArguments("--disable-notifications");

        WebDriver driver = new ChromeDriver(options);
        
        // Page load timeout prevents hanging on slow third-party scripts
        driver.manage().timeouts().pageLoadTimeout(Duration.ofSeconds(30));
        
        // ZERO implicit wait by default to avoid race conditions
        driver.manage().timeouts().implicitlyWait(Duration.ofSeconds(0));

        return driver;
    }
}

// ❌ NEVER USE Thread.sleep() — it pauses the JVM blindly, wasting CI minutes
// Thread.sleep(5000);

// ✅ Standard Explicit Wait: Polls every 500ms until condition is satisfied or timeout
WebDriverWait wait = new WebDriverWait(driver, Duration.ofSeconds(10));
WebElement transferBtn = wait.until(
    ExpectedConditions.elementToBeClickable(By.id("confirmTransferBtn"))
);
transferBtn.click();

// ✅ Advanced Fluent Wait: Custom polling frequency & exception filtering
Wait<WebDriver> fluentWait = new FluentWait<>(driver)
    .withTimeout(Duration.ofSeconds(15))
    .pollingEvery(Duration.ofMillis(250))
    .ignoring(NoSuchElementException.class)
    .ignoring(StaleElementReferenceException.class);

WebElement balanceBadge = fluentWait.until(d -> {
    WebElement el = d.findElement(By.id("accountBalance"));
    return el.getText().contains("$") ? el : null;
});

package com.testerrank.tests;

import org.openqa.selenium.By;
import org.openqa.selenium.WebDriver;
import org.openqa.selenium.WebElement;
import org.openqa.selenium.chrome.ChromeDriver;
import org.openqa.selenium.support.ui.ExpectedConditions;
import org.openqa.selenium.support.ui.WebDriverWait;
import org.testng.Assert;
import org.testng.annotations.AfterMethod;
import org.testng.annotations.BeforeMethod;
import org.testng.annotations.Test;
import java.time.Duration;

public class BankingLoginTest {

    private WebDriver driver;
    private WebDriverWait wait;

    @BeforeMethod
    public void setUp() {
        driver = new ChromeDriver();
        driver.manage().window().maximize();
        wait = new WebDriverWait(driver, Duration.ofSeconds(10));
    }

    @Test(description = "Verify successful user login into ISB NetBanking Portal")
    public void testValidBankingLogin() {
        // Navigate to the live TesterRank Banking Portal
        driver.get("https://www.testerrank.com/banking/login");

        // Wait for login inputs to become visible
        WebElement userIdInput = wait.until(
            ExpectedConditions.visibilityOfElementLocated(By.id("userId"))
        );
        WebElement passwordInput = driver.findElement(By.id("password"));
        WebElement loginButton = driver.findElement(By.id("loginBtn"));

        // Fill credentials and click sign in
        userIdInput.sendKeys("user101");
        passwordInput.sendKeys("BankingPass@2026");
        loginButton.click();

        // Wait for dashboard account header to load
        WebElement dashboardHeader = wait.until(
            ExpectedConditions.visibilityOfElementLocated(By.id("accountOverviewHeader"))
        );

        // Assert that the user is authenticated successfully
        Assert.assertTrue(dashboardHeader.isDisplayed(), "Dashboard header should be visible upon login");
        Assert.assertTrue(driver.getCurrentUrl().contains("/banking"), "User should remain in banking domain");
    }

    @AfterMethod
    public void tearDown() {
        if (driver != null) {
            driver.quit(); // Closes all browser windows and kills driver process
        }
    }
}

public class BaseTest {
    // ThreadLocal ensures every thread maintains its own isolated WebDriver instance
    private static final ThreadLocal<WebDriver> driverThread = new ThreadLocal<>();

    public static WebDriver getDriver() {
        return driverThread.get();
    }

    @BeforeMethod
    public void setUp() {
        WebDriver driver = DriverFactory.createChromeDriver(true);
        driverThread.set(driver);
    }

    @AfterMethod
    public void tearDown() {
        WebDriver driver = driverThread.get();
        if (driver != null) {
            driver.quit();
            driverThread.remove(); // Prevents memory leaks in CI agent worker pools
        }
    }
}