Browser profile configuration in Selenium Python - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

What is the output of this Selenium Python code snippet?

Consider the following Selenium code that sets a Firefox profile preference and then retrieves it. What will be printed?

Selenium Python

from selenium import webdriver
from selenium.webdriver.firefox.options import Options

profile = webdriver.FirefoxProfile()
profile.set_preference('browser.startup.homepage', 'https://example.com')
profile.update_preferences()

options = Options()
driver = webdriver.Firefox(firefox_profile=profile, options=options)

homepage = profile._preferences.get('browser.startup.homepage')
print(homepage)
driver.quit()

A https://example.com

B SyntaxError

C KeyError exception

D None

💡 Hint

Check how to access preferences from the FirefoxProfile object after setting them.

The default_preferences attribute does not reflect the updated preferences set by set_preference. Therefore, get returns None.

❓ assertion

intermediate

Which assertion correctly verifies the browser profile preference was set?

You want to check that the Firefox profile has the homepage set to https://example.com. Which assertion is correct?

Selenium Python

from selenium import webdriver

profile = webdriver.FirefoxProfile()
profile.set_preference('browser.startup.homepage', 'https://example.com')

# Which assertion below is correct?

A assert profile.default_preferences['browser.startup.homepage'] == 'https://example.com'

B assert profile._preferences['browser.startup.homepage'] == 'https://example.com'

C assert profile.get_preference('browser.startup.homepage') == 'https://example.com'

D assert profile._preferences.get('browser.startup.homepage') == 'https://example.com'

💡 Hint

Look inside the FirefoxProfile object to find where preferences are stored.

The _preferences dictionary holds the preferences set by set_preference. Using get avoids KeyError if missing.

🔧 Debug

advanced

Why does this Selenium Firefox profile code fail to load the custom homepage?

The test sets a custom homepage but Firefox opens with the default page. Identify the bug.

Selenium Python

from selenium import webdriver

profile = webdriver.FirefoxProfile()
profile.set_preference('browser.startup.homepage', 'https://custompage.com')

driver = webdriver.Firefox(firefox_profile=profile)
# driver.get('about:home')  # This line causes the homepage override

# Expected homepage is https://custompage.com but it opens default Firefox page.

A Missing call to profile.update_preferences() before creating driver

B Calling driver.get('about:home') overrides homepage setting

C Using deprecated firefox_profile argument instead of options

D Homepage preference key is incorrect

💡 Hint

Think about what driver.get('about:home') does after browser starts.

Calling driver.get('about:home') navigates explicitly to Firefox's default home page, ignoring the profile's homepage setting.

❓ framework

advanced

How to correctly apply a Firefox profile in Selenium with modern options?

Which code snippet correctly applies a Firefox profile using Selenium's recommended approach?

A

profile = webdriver.FirefoxProfile()
profile.set_preference('key', 'value')
options = webdriver.FirefoxOptions()
options.profile = profile
driver = webdriver.Firefox(options=options)

B

profile = webdriver.FirefoxProfile()
profile.set_preference('key', 'value')
driver = webdriver.Firefox(firefox_profile=profile)

C

options = webdriver.FirefoxOptions()
options.set_preference('key', 'value')
driver = webdriver.Firefox(options=options)

D

profile = webdriver.FirefoxProfile()
profile.set_preference('key', 'value')
options = webdriver.FirefoxOptions()
driver = webdriver.Firefox(firefox_profile=profile, options=options)

💡 Hint

Check how to assign profile to options in Selenium 4+.

In Selenium 4+, the FirefoxProfile should be assigned to options.profile before passing options to the driver constructor.

🧠 Conceptual

expert

What is the main advantage of using a browser profile in automated tests?

Why do testers use browser profiles when running automated Selenium tests?

A To avoid writing test assertions by preloading test data

B To speed up test execution by disabling all browser features

C To customize browser settings and extensions for consistent test environments

D To automatically generate test reports after each test run

💡 Hint

Think about controlling browser behavior and environment.

Browser profiles allow setting preferences, extensions, and other configurations to ensure tests run in a controlled, repeatable environment.