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Selenium cheatsheet

A one-page reference for Selenium. For WebDriver architecture and interview Q&A, see the complete guide.

📖 Full guide: Selenium →

Locator strategies​

driver.findElement(By.id("username"));
driver.findElement(By.cssSelector(".btn-primary"));
driver.findElement(By.xpath("//button[text()='Submit']"));

Prefer id/CSS over XPath — faster, more resilient to markup changes.

Waits (avoid the classic flakiness bug)​

WebDriverWait wait = new WebDriverWait(driver, Duration.ofSeconds(10));
wait.until(ExpectedConditions.elementToBeClickable(By.id("submit")));

Never mix Thread.sleep() with explicit waits — and never set both an implicit and explicit wait globally, they compound unpredictably.

See: Waits — and the Classic Flakiness Bug

Page Object Model​

public class LoginPage {
  private WebDriver driver;
  private By username = By.id("username");

  public void login(String user, String pass) {
    driver.findElement(username).sendKeys(user);
    driver.findElement(By.id("submit")).click();
  }
}

Frames, alerts, windows​

driver.switchTo().frame("payment-frame");
driver.switchTo().alert().accept();
for (String handle : driver.getWindowHandles()) {
  driver.switchTo().window(handle);
}

Selenium Grid​

docker run -d -p 4444:4444 selenium/hub
docker run -d --link hub selenium/node-chrome
new RemoteWebDriver(new URL("http://hub:4444"), capabilities);

Distributes tests across many browsers/machines in parallel.

Actions API​

Actions actions = new Actions(driver);
actions.dragAndDrop(source, target).perform();
actions.moveToElement(menu).click(subItem).perform();

Common flakiness pitfalls​

  • Hardcoded sleeps instead of explicit waits.
  • Stale element references after a page re-render.
  • Not isolating test data — parallel tests colliding on shared state.
See: Common Flakiness Pitfalls

Framework & CI notes​

  • Pair with TestNG/JUnit for assertions and parallel execution.
  • Run headless in CI (--headless=new Chrome flag) for speed.
  • Screenshot on failure — the highest-leverage CI debugging aid.