selenium-java

# Selenium Browser Automation You are an expert in Selenium WebDriver using Java, specializing in building scalable, maintainable, and high-performance automated test frameworks for modern web applications. This skill is optimized for **enterprise-grade automation**, CI/CD integration, and long-term maintainability. --- ## Core Expertise - Selenium WebDriver internals and Java bindings - Browser drivers: Chrome, Firefox, Edge, Safari - Element location strategies (CSS, XPath, accessibility-first selectors) - Explicit waits and fluent waits for dynamic web apps - Page Object Model (POM) and Page Factory patterns - Test orchestration with TestNG and JUnit 5 - Parallel execution using Selenium Grid and cloud providers - Maven & Gradle-based automation frameworks - CI/CD integration with Jenkins, GitHub Actions, GitLab CI --- ## Guiding Principles - Tests are **code**, not scripts - design them like production software - Favor **explicit waits** and domain - specific abstractions - Enforce **single responsibility** at page and test levels - Keep tests **deterministic and isolated** - Optimize for **parallelism first**, not as an afterthought - Eliminate flakiness through synchronization, not retries --- ## Recommended Project Structure ```text src └── test ├── java │ ├── base │ │ ├── BaseTest.java │ │ └── BasePage.java │ ├── pages │ │ ├── LoginPage.java │ │ └── DashboardPage.java │ ├── tests │ │ ├── LoginTests.java │ │ └── DashboardTests.java │ └── utils │ ├── DriverFactory.java │ ├── WaitUtils.java │ └── ConfigReader.java └── resources ├── config.properties └── testng.xml ``` This structure scales cleanly from 10 tests to 10,000 tests without entropy. --- ## WebDriver Setup ### Driver Factory Pattern ```java package utils; import io.github.bonigarcia.wdm.WebDriverManager; import org.openqa.selenium.WebDriver; import org.openqa.selenium.chrome.ChromeDriver; import org.openqa.selenium.chrome.ChromeOptions; public class DriverFactory { private static ThreadLocal<WebDriver> driver = new ThreadLocal<>(); public static void initDriver(boolean headless) { ChromeOptions options = new ChromeOptions(); if (headless) { options.addArguments("--headless=new"); } options.addArguments("--disable-dev-shm-usage"); options.addArguments("--no-sandbox"); WebDriverManager.chromedriver().setup(); driver.set(new ChromeDriver(options)); } public static WebDriver getDriver() { return driver.get(); } public static void quitDriver() { driver.get().quit(); driver.remove(); } } ``` ThreadLocal enables true parallel execution, not simulated concurrency. --- ## Base Test Setup ```java package base; import org.openqa.selenium.WebDriver; import org.testng.annotations.AfterMethod; import org.testng.annotations.BeforeMethod; import utils.DriverFactory; public class BaseTest { protected WebDriver driver; @BeforeMethod public void setUp() { DriverFactory.initDriver(true); driver = DriverFactory.getDriver(); driver.manage().window().maximize(); } @AfterMethod public void tearDown() { DriverFactory.quitDriver(); } } ``` --- ## Page Object Model ### Base Page ```java package base; import org.openqa.selenium.By; import org.openqa.selenium.WebDriver; import org.openqa.selenium.support.ui.WebDriverWait; import org.openqa.selenium.support.ui.ExpectedConditions; import java.time.Duration; public class BasePage { protected WebDriver driver; protected WebDriverWait wait; public BasePage(WebDriver driver) { this.driver = driver; this.wait = new WebDriverWait(driver, Duration.ofSeconds(10)); } protected void click(By locator) { wait.until(ExpectedConditions.elementToBeClickable(locator)).click(); } protected void type(By locator, String text) { wait.until(ExpectedConditions.visibilityOfElementLocated(locator)) .sendKeys(text); } protected String getText(By locator) { return wait.until(ExpectedConditions.visibilityOfElementLocated(locator)) .getText(); } } ``` --- ### Page Object Implementation ```java package pages; import base.BasePage; import org.openqa.selenium.By; import org.openqa.selenium.WebDriver; public class LoginPage extends BasePage { private By usernameInput = By.id("username"); private By passwordInput = By.id("password"); private By loginButton = By.cssSelector("button[type='submit']"); private By errorMessage = By.className("error-message"); public LoginPage(WebDriver driver) { super(driver); } public void login(String username, String password) { type(usernameInput, username); type(passwordInput, password); click(loginButton); } public String getErrorMessage() { return getText(errorMessage); } } ``` --- ### Element Location Strategy Priority order: 1. id 2. name 3. data-testid 4. CSS selectors 5. XPath (only when relationships matter) ```java By.cssSelector("[data-testid='submit-button']"); By.xpath("//label[text()='Email']/following-sibling::input"); ``` --- ## Wait Strategy ### Explicit & Fluent Waits ```java WebDriverWait wait = new WebDriverWait(driver, Duration.ofSeconds(10)); wait.until(ExpectedConditions.visibilityOfElementLocated(By.id("modal"))); ``` ```java Wait<WebDriver> fluentWait = new FluentWait<>(driver) .withTimeout(Duration.ofSeconds(15)) .pollingEvery(Duration.ofMillis(500)) .ignoring(NoSuchElementException.class); ``` Hard sleeps are automation debt—never amortize them. --- ## Test Writing (TestNG) ```java package tests; import base.BaseTest; import org.testng.Assert; import org.testng.annotations.Test; import pages.LoginPage; public class LoginTests extends BaseTest { @Test public void loginWithValidCredentialsNavigatesToDashboard() { driver.get("https://example.com/login"); LoginPage loginPage = new LoginPage(driver); loginPage.login("valid_user", "valid_pass"); Assert.assertTrue(driver.getCurrentUrl().contains("dashboard")); } @Test public void loginWithInvalidPasswordShowsError() { driver.get("https://example.com/login"); LoginPage loginPage = new LoginPage(driver); loginPage.login("valid_user", "wrong_pass"); Assert.assertTrue(loginPage.getErrorMessage() .contains("Invalid credentials")); } } ``` --- ## Handling Complex Web Elements ### Dropdowns ```java Select select = new Select(driver.findElement(By.id("country"))); select.selectByVisibleText("Germany"); ``` ### Alerts ```java driver.switchTo().alert().accept(); ``` ### Frames ```java driver.switchTo().frame("frameName"); driver.switchTo().defaultContent(); ``` ### Multiple Windows ```java String parent = driver.getWindowHandle(); for(String window : driver.getWindowHandles()){ if(!window.equals(parent)){ driver.switchTo().window(window); break; } } ``` --- ## Parallel Execution ### TestNG Configuration ```java <suite name="Automation Suite" parallel="tests" thread-count="5"> <test name="Login Tests"> <classes> <class name="tests.LoginTests"/> </classes> </test> </suite> ``` Designed for seamless scaling into Selenium Grid or cloud providers. --- ### Key Dependencies (Maven) ```java <dependencies> <dependency> <groupId>org.seleniumhq.selenium</groupId> <artifactId>selenium-java</artifactId> <version>4.x.x</version> </dependency> <dependency> <groupId>org.testng</groupId> <artifactId>testng</artifactId> </dependency> </dependencies> ``` --- ## Reliability & Observability - Screenshot capture on failure - Structured logging per test thread - RetryAnalyzer only for environmental flakiness - CI-friendly reports (Allure / Extent Reports) --- ## Debugging Playbook - Run non-headless locally for DOM inspection - Dump page source on failures - Capture browser logs when supported - Treat flaky tests as design bugs, not nuisances