Headless execution in Selenium Java - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

Output of Selenium Headless Chrome Setup

What will be the output of the following Java Selenium code snippet when run in headless mode?

Selenium Java

import org.openqa.selenium.WebDriver;
import org.openqa.selenium.chrome.ChromeDriver;
import org.openqa.selenium.chrome.ChromeOptions;

public class HeadlessTest {
    public static void main(String[] args) {
        ChromeOptions options = new ChromeOptions();
        options.addArguments("--headless");
        WebDriver driver = new ChromeDriver(options);
        driver.get("https://example.com");
        String title = driver.getTitle();
        System.out.println(title);
        driver.quit();
    }
}

A Prints an empty string and exits normally

B Throws a WebDriverException due to missing GUI

C Prints "Example Domain" and exits normally

D Throws a NullPointerException at getTitle()

💡 Hint

Headless mode runs browser without GUI but still loads pages fully.

In headless mode, Chrome loads pages normally but without opening a visible window. The title of https://example.com is "Example Domain", so the code prints that and exits cleanly.

❓ assertion

intermediate

Correct Assertion for Headless Page Title

Which assertion correctly verifies the page title in a Selenium Java test running in headless mode?

Selenium Java

import static org.junit.jupiter.api.Assertions.assertEquals;

// Assume driver is a valid WebDriver instance running headless
String actualTitle = driver.getTitle();

A assertFalse(actualTitle.isEmpty());

B assertEquals(actualTitle, "Example Domain");

C assertTrue(actualTitle.contains("Example"));

D assertEquals("Example Domain", actualTitle);

💡 Hint

Check the order of expected and actual in assertEquals.

The correct order in assertEquals is assertEquals(expected, actual). Option D uses this order and checks exact title match.

🔧 Debug

advanced

Debugging Headless Chrome Timeout

A Selenium test running Chrome in headless mode fails with a timeout error when loading a page. Which is the most likely cause?

A Incorrect ChromeDriver version incompatible with Chrome browser

B Missing --disable-gpu argument causing rendering issues

C Headless mode disables network requests by default

D Page requires user interaction which headless mode cannot perform

💡 Hint

Check compatibility between driver and browser versions.

Timeouts often happen if ChromeDriver version does not match the installed Chrome browser version, causing failures to load pages.

🧠 Conceptual

advanced

Advantages of Headless Browser Testing

Which of the following is NOT an advantage of running Selenium tests in headless mode?

A Ability to run tests on servers without display environments

B Easier debugging by visually seeing browser actions

C Faster test execution due to no GUI rendering

D Reduced resource usage compared to full browser mode

💡 Hint

Think about what headless mode means for visual feedback.

Headless mode does not show a GUI, so you cannot visually see browser actions, making debugging harder, not easier.

❓ framework

expert

Configuring Headless Mode in Selenium Test Framework

In a Java Selenium test framework using JUnit 5, which code snippet correctly configures ChromeDriver to run all tests in headless mode with proper setup and teardown?

A

private WebDriver driver;

@BeforeEach
void setup() {
  ChromeOptions options = new ChromeOptions();
  options.addArguments("--headless");
  driver = new ChromeDriver(options);
}

@AfterEach
void teardown() {
  driver.quit();
}

B

private WebDriver driver;

@BeforeAll
static void setup() {
  ChromeOptions options = new ChromeOptions();
  options.addArguments("--headless");
  driver = new ChromeDriver(options);
}

@AfterAll
static void teardown() {
  driver.quit();
}

C

private static WebDriver driver;

@BeforeEach
void setup() {
  ChromeOptions options = new ChromeOptions();
  options.addArguments("--headless");
  driver = new ChromeDriver(options);
}

@AfterEach
void teardown() {
  driver.quit();
}

D

private static WebDriver driver;

@BeforeAll
static void setup() {
  ChromeOptions options = new ChromeOptions();
  options.addArguments("--headless");
  driver = new ChromeDriver(options);
}

@AfterAll
static void teardown() {
  driver.quit();
}

💡 Hint

Remember JUnit 5 lifecycle annotations and static context rules.

In JUnit 5, @BeforeEach and @AfterEach methods are instance methods (non-static). Driver should be instance variable to avoid sharing state between tests. Option A follows this correctly.