Complete Example — Banking Portal Test Suite

import org.openqa.selenium.WebDriver;
import org.openqa.selenium.chrome.ChromeDriver;
import org.openqa.selenium.chrome.ChromeOptions;
import org.openqa.selenium.support.ui.WebDriverWait;
import org.testng.annotations.*;
import java.time.Duration;

public class BaseTest {
    private static ThreadLocal<WebDriver> driverThread =
        new ThreadLocal<>();
    private static ThreadLocal<WebDriverWait> waitThread =
        new ThreadLocal<>();

    @BeforeMethod
    @Parameters({"baseUrl"})
    public void setUp(@Optional("https://www.testerrank.com") String baseUrl) {
        ChromeOptions options = new ChromeOptions();
        options.addArguments("--start-maximized");

        WebDriver driver = new ChromeDriver(options);
        driverThread.set(driver);
        waitThread.set(new WebDriverWait(driver, Duration.ofSeconds(10)));

        driver.get(baseUrl + "/banking");
    }

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

    public WebDriverWait getWait() {
        return waitThread.get();
    }

    @AfterMethod
    public void tearDown() {
        WebDriver driver = driverThread.get();
        if (driver != null) {
            driver.quit();
            driverThread.remove();
            waitThread.remove();
        }
    }
}

import org.openqa.selenium.By;
import org.openqa.selenium.WebElement;
import org.openqa.selenium.support.ui.ExpectedConditions;
import org.testng.Assert;
import org.testng.annotations.DataProvider;
import org.testng.annotations.Test;
import org.testng.asserts.SoftAssert;

public class BankingLoginTest extends BaseTest {

    @Test(priority = 1, groups = {"smoke"},
          description = "Verify login page loads correctly")
    public void testLoginPageLoads() {
        SoftAssert soft = new SoftAssert();

        soft.assertTrue(
            getDriver().getTitle().contains("Banking"),
            "Title should contain Banking");

        WebElement usernameField = getDriver()
            .findElement(By.id("username"));
        soft.assertTrue(usernameField.isDisplayed(),
            "Username field should be visible");

        WebElement passwordField = getDriver()
            .findElement(By.id("password"));
        soft.assertTrue(passwordField.isDisplayed(),
            "Password field should be visible");

        WebElement loginBtn = getDriver()
            .findElement(By.cssSelector("button[type='submit']"));
        soft.assertTrue(loginBtn.isEnabled(),
            "Login button should be enabled");

        soft.assertAll();
    }

    @Test(priority = 2, groups = {"smoke", "regression"},
          description = "Verify successful login with valid credentials")
    public void testSuccessfulLogin() {
        getDriver().findElement(By.id("username")).sendKeys("testuser");
        getDriver().findElement(By.id("password")).sendKeys("password123");
        getDriver().findElement(
            By.cssSelector("button[type='submit']")).click();

        getWait().until(
            ExpectedConditions.urlContains("/dashboard"));

        Assert.assertTrue(
            getDriver().getCurrentUrl().contains("/dashboard"),
            "Should redirect to dashboard after login");
    }

    @DataProvider(name = "invalidLogins")
    public Object[][] invalidLoginData() {
        return new Object[][] {
            { "invalid",   "wrong",       "Invalid credentials" },
            { "",          "password123", "Username is required" },
            { "testuser",  "",            "Password is required" },
        };
    }

    @Test(priority = 3, groups = {"regression"},
          dataProvider = "invalidLogins",
          description = "Verify error messages for invalid login attempts")
    public void testInvalidLogin(String username, String password,
                                 String expectedError) {
        if (!username.isEmpty()) {
            getDriver().findElement(By.id("username"))
                .sendKeys(username);
        }
        if (!password.isEmpty()) {
            getDriver().findElement(By.id("password"))
                .sendKeys(password);
        }
        getDriver().findElement(
            By.cssSelector("button[type='submit']")).click();

        WebElement error = getWait().until(
            ExpectedConditions.visibilityOfElementLocated(
                By.cssSelector(".error-message")
            )
        );

        Assert.assertTrue(error.getText().contains(expectedError),
            "Error should contain: " + expectedError);
    }

    @Test(priority = 4, groups = {"regression"},
          dependsOnMethods = {"testSuccessfulLogin"},
          description = "Verify dashboard loads after login")
    public void testDashboardAfterLogin() {
        // Login first
        getDriver().findElement(By.id("username")).sendKeys("testuser");
        getDriver().findElement(By.id("password")).sendKeys("password123");
        getDriver().findElement(
            By.cssSelector("button[type='submit']")).click();

        getWait().until(
            ExpectedConditions.urlContains("/dashboard"));

        // Verify dashboard elements
        SoftAssert soft = new SoftAssert();

        soft.assertTrue(
            getDriver().findElement(By.id("balance")).isDisplayed(),
            "Balance should be visible");
        soft.assertTrue(
            getDriver().findElement(By.id("welcome-message"))
                .isDisplayed(),
            "Welcome message should be visible");

        soft.assertAll();
    }
}

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE suite SYSTEM "https://testng.org/testng-1.0.dtd">

<suite name="Banking Suite" parallel="classes" thread-count="2">

    <parameter name="baseUrl" value="https://www.testerrank.com" />

    <listeners>
        <listener class-name="com.autopractice.listeners.TestListener" />
        <listener class-name="com.autopractice.listeners.RetryTransformer" />
    </listeners>

    <test name="Banking Tests">
        <groups>
            <run>
                <include name="smoke" />
                <include name="regression" />
            </run>
        </groups>
        <classes>
            <class name="com.autopractice.tests.BankingLoginTest" />
        </classes>
    </test>

</suite>