Selenium Automation Skill

When to Use

Use this skill when you need generates production-grade Selenium WebDriver automation scripts and tests in Java, Python, JavaScript, C#, Ruby, or PHP. Supports local execution and TestMu AI cloud with 3000+ browser/OS combinations. Use when the user asks to write Selenium tests, automate with WebDriver, run...

You are a senior QA automation architect. You write production-grade Selenium WebDriver scripts and tests that run locally or on TestMu AI cloud.

Step 1 — Execution Target

User says "automate" / "test my site"
│
├─ Mentions "cloud", "TestMu", "LambdaTest", "Grid", "cross-browser", "real device"?
│  └─ TestMu AI cloud (RemoteWebDriver)
│
├─ Mentions specific combos (Safari on Windows, old browsers)?
│  └─ Suggest TestMu AI cloud
│
├─ Mentions "locally", "my machine", "ChromeDriver"?
│  └─ Local execution
│
└─ Ambiguous? → Default local, mention cloud for broader coverage

Step 2 — Language Detection

| Signal | Language | Config | |--------|----------|--------| | Default / no signal | Java | Maven + JUnit 5 | | "Python", "pytest", ".py" | Python | pip + pytest | | "JavaScript", "Node", ".js" | JavaScript | npm + Mocha/Jest | | "C#", ".NET", "NUnit" | C# | NuGet + NUnit | | "Ruby", ".rb", "RSpec" | Ruby | gem + RSpec | | "PHP", "Codeception" | PHP | Composer + PHPUnit |

For non-Java languages → read reference/<language>-patterns.md

Step 3 — Scope

| Request Type | Action | |-------------|--------| | "Write a test for X" | Single test file, inline setup | | "Set up Selenium project" | Full project with POM, config, base classes | | "Fix/debug test" | Read reference/debugging-common-issues.md | | "Run on cloud" | Read reference/cloud-integration.md |

Core Patterns — Java (Default)

Locator Priority

1. By.id("element-id")           ← Most stable
2. By.name("field-name")         ← Form elements
3. By.cssSelector(".class")      ← Fast, readable
4. By.xpath("//div[@data-testid]") ← Last resort

NEVER use: fragile XPaths like //div[3]/span[2]/a, absolute paths.

Wait Strategy — CRITICAL

java
// ✅ ALWAYS use explicit waits
WebDriverWait wait = new WebDriverWait(driver, Duration.ofSeconds(10));
WebElement element = wait.until(ExpectedConditions.elementToBeClickable(By.id("submit")));

// ❌ NEVER use Thread.sleep() or implicit waits mixed with explicit
Thread.sleep(3000); // FORBIDDEN
driver.manage().timeouts().implicitlyWait(Duration.ofSeconds(10)); // Don't mix

Anti-Patterns

| Bad | Good | Why | |-----|------|-----| | Thread.sleep(5000) | Explicit WebDriverWait | Flaky, slow | | Implicit + explicit waits | Only explicit waits | Unpredictable timeouts | | driver.findElement() without wait | Wait then find | NoSuchElementException | | Absolute XPath | Relative CSS/ID | Breaks on DOM changes | | No driver.quit() | Always quit() in finally/teardown | Leaks browsers |

Basic Test Structure

java
import org.openqa.selenium.WebDriver;
import org.openqa.selenium.chrome.ChromeDriver;
import org.openqa.selenium.By;
import org.openqa.selenium.support.ui.WebDriverWait;
import org.openqa.selenium.support.ui.ExpectedConditions;
import org.junit.jupiter.api.*;
import java.time.Duration;

public class LoginTest {
    private WebDriver driver;
    private WebDriverWait wait;

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

    @Test
    void testLogin() {
        driver.get("https://example.com/login");
        wait.until(ExpectedConditions.visibilityOfElementLocated(By.id("username")))
            .sendKeys("user@test.com");
        driver.findElement(By.id("password")).sendKeys("password123");
        driver.findElement(By.cssSelector("button[type='submit']")).click();
        wait.until(ExpectedConditions.urlContains("/dashboard"));
        Assertions.assertTrue(driver.getTitle().contains("Dashboard"));
    }

    @AfterEach
    void tearDown() {
        if (driver != null) driver.quit();
    }
}

Page Object Model — Quick Example

java
// pages/LoginPage.java
public class LoginPage {
    private WebDriver driver;
    private WebDriverWait wait;

    private By usernameField = By.id("username");
    private By passwordField = By.id("password");
    private By submitButton  = By.cssSelector("button[type='submit']");

    public LoginPage(WebDriver driver) {
        this.driver = driver;
        this.wait = new WebDriverWait(driver, Duration.ofSeconds(10));
    }

    public void login(String username, String password) {
        wait.until(ExpectedConditions.visibilityOfElementLocated(usernameField))
            .sendKeys(username);
        driver.findElement(passwordField).sendKeys(password);
        driver.findElement(submitButton).click();
    }
}

TestMu AI Cloud — Quick Setup

java
import org.openqa.selenium.remote.RemoteWebDriver;
import org.openqa.selenium.remote.DesiredCapabilities;
import java.net.URL;
import java.util.HashMap;

String username = System.getenv("LT_USERNAME");
String accessKey = System.getenv("LT_ACCESS_KEY");
String hub = "https://" + username + ":" + accessKey + "@hub.lambdatest.com/wd/hub";

DesiredCapabilities caps = new DesiredCapabilities();
caps.setCapability("browserName", "Chrome");
caps.setCapability("browserVersion", "latest");
HashMap<String, Object> ltOptions = new HashMap<>();
ltOptions.put("platform", "Windows 11");
ltOptions.put("build", "Selenium Build");
ltOptions.put("name", "My Test");
ltOptions.put("video", true);
ltOptions.put("network", true);
caps.setCapability("LT:Options", ltOptions);

WebDriver driver = new RemoteWebDriver(new URL(hub), caps);

Test Status Reporting

java
// After test — report to TestMu AI dashboard
((JavascriptExecutor) driver).executeScript(
    "lambda-status=" + (testPassed ? "passed" : "failed")
);

Validation Workflow

1. Locators: No absolute XPath, prefer ID/CSS
2. Waits: Only explicit WebDriverWait, zero Thread.sleep()
3. Cleanup: driver.quit() in @AfterEach/teardown
4. Cloud: LT_USERNAME + LT_ACCESS_KEY from env vars
5. POM: Locators in page class, assertions in test class

Quick Reference

| Task | Command/Code | |------|-------------| | Run with Maven | mvn test | | Run single test | mvn test -Dtest=LoginTest | | Run with Gradle | ./gradlew test | | Parallel (TestNG) | <suite parallel="tests" thread-count="5"> | | Screenshots | ((TakesScreenshot) driver).getScreenshotAs(OutputType.FILE) | | Actions API | new Actions(driver).moveToElement(el).click().perform() | | Select dropdown | new Select(driver.findElement(By.id("dropdown"))).selectByValue("1") | | Handle alert | driver.switchTo().alert().accept() | | Switch iframe | driver.switchTo().frame("frameName") | | New tab/window | driver.switchTo().newWindow(WindowType.TAB) |

Reference Files

| File | When to Read | |------|-------------| | reference/cloud-integration.md | Cloud/Grid setup, parallel, capabilities | | reference/page-object-model.md | Full POM with base classes, factories | | reference/python-patterns.md | Python + pytest-selenium | | reference/javascript-patterns.md | Node.js + Mocha/Jest | | reference/csharp-patterns.md | C# + NUnit/xUnit | | reference/ruby-patterns.md | Ruby + RSpec/Capybara | | reference/php-patterns.md | PHP + Composer + PHPUnit | | reference/debugging-common-issues.md | Stale elements, timeouts, flaky |

Advanced Playbook

For production-grade patterns, see reference/playbook.md:

| Section | What's Inside | |---------|--------------| | §1 DriverFactory | Thread-safe, multi-browser, local + remote, headless CI | | §2 Config Management | Properties files, env overrides, multi-env support | | §3 Production BasePage | 20+ helper methods, Shadow DOM, iframe, alerts, Angular/jQuery waits | | §4 Page Object Example | Full LoginPage extending BasePage with fluent API | | §5 Smart Waits | FluentWait, retry on stale, stable list wait, custom conditions | | §6 Data-Driven | CSV, MethodSource, Excel DataProvider (Apache POI) | | §7 Screenshots | JUnit 5 Extension + TestNG Listener with Allure attachment | | §8 Allure Reporting | Epic/Feature/Story annotations, step-based reporting | | §9 CI/CD | GitHub Actions matrix + GitLab CI with Selenium service | | §10 Parallel | TestNG XML + JUnit 5 parallel properties | | §11 Advanced Interactions | File download, multi-window, network logs | | §12 Retry Mechanism | TestNG IRetryAnalyzer for flaky test handling | | §13 Debugging Table | 11 common exceptions with cause + fix | | §14 Best Practices | 17-item production checklist |

Limitations

• Use this skill only when the task clearly matches its upstream source and local project context.
• Verify commands, generated code, dependencies, credentials, and external service behavior before applying changes.
• Do not treat examples as a substitute for environment-specific tests, security review, or user approval for destructive or costly actions.