Browser options and capabilities in Selenium Python

Introduction

Browser options and capabilities let you control how the browser behaves during automated tests. This helps make tests more reliable and flexible.

When you want to run tests in headless mode (without opening the browser window).

When you need to disable browser notifications or pop-ups during tests.

When you want to set the browser window size or start maximized.

When you want to add custom browser preferences like disabling images to speed up tests.

When you want to specify browser capabilities like accepting insecure certificates.

Syntax

Selenium Python

from selenium import webdriver
from selenium.webdriver.chrome.options import Options

options = Options()
options.add_argument('--headless')  # Run browser in headless mode
options.add_argument('--window-size=1920,1080')  # Set window size

driver = webdriver.Chrome(options=options)

Use Options() to set browser-specific options.

Use add_argument() to add command-line switches to the browser.

Examples

This disables browser notifications during tests.

Selenium Python

options = Options()
options.add_argument('--disable-notifications')
driver = webdriver.Chrome(options=options)

This starts the browser window maximized.

Selenium Python

options = Options()
options.add_argument('--start-maximized')
driver = webdriver.Chrome(options=options)

This sets the browser to accept insecure SSL certificates.

Selenium Python

capabilities = webdriver.DesiredCapabilities.CHROME.copy()
capabilities['acceptInsecureCerts'] = True
driver = webdriver.Chrome(desired_capabilities=capabilities)

Sample Program

This script opens the browser in headless mode with a window size of 800x600, navigates to example.com, prints the page title, and then closes the browser.

Selenium Python

from selenium import webdriver
from selenium.webdriver.chrome.options import Options
import time

options = Options()
options.add_argument('--headless')
options.add_argument('--window-size=800,600')

# Create driver with options
driver = webdriver.Chrome(options=options)

# Open a website
driver.get('https://example.com')

# Print the page title
print(driver.title)

# Close the browser
driver.quit()

Important Notes

Always quit the driver with driver.quit() to close the browser properly.

Headless mode is useful for running tests on servers without a display.

Use browser options to make tests faster and avoid unwanted pop-ups or dialogs.

Summary

Browser options let you customize how the browser runs during tests.

Use options to run headless, set window size, disable notifications, and more.

Capabilities can set browser behaviors like accepting insecure certificates.

Practice

1. What is the main purpose of using Options in Selenium WebDriver for browsers?

easy

A. To customize browser settings like headless mode or window size

B. To write test assertions for page elements

C. To locate elements on a web page

D. To generate test reports automatically

Solution

1. Step 1: Understand what Options configure

   Options allow you to set how the browser behaves during tests, such as running headless or setting window size.

2. Step 2: Differentiate Options from other tasks

   Options do not handle locating elements, assertions, or reports; those are separate tasks.

3. Final Answer:

   To customize browser settings like headless mode or window size -> Option A

4. Quick Check:

   Options = Browser customization [OK]

Hint: Options control browser behavior, not test logic [OK]

Common Mistakes:

• Confusing Options with element locators
• Thinking Options generate reports
• Mixing Options with assertion logic

2. Which of the following is the correct way to set Chrome to run in headless mode using Selenium in Python?

easy

A. options = webdriver.ChromeOptions()
options.add_argument('--headless')

B. options = webdriver.ChromeOptions()
options.set_headless(True)

C. options = webdriver.ChromeOptions()
options.headless = True

D. options = webdriver.ChromeOptions()
options.add_option('headless')

Solution

1. Step 1: Recall correct method to add arguments

   In Selenium Python, add_argument is used to add command line switches like '--headless'.

2. Step 2: Check each option's syntax

   Only options = webdriver.ChromeOptions() options.add_argument('--headless') uses add_argument('--headless') correctly; others use invalid or non-existent methods.

3. Final Answer:

   options = webdriver.ChromeOptions() options.add_argument('--headless') -> Option A

4. Quick Check:

   Use add_argument('--headless') for headless mode [OK]

Hint: Use add_argument('--headless') to enable headless mode [OK]

Common Mistakes:

• Using non-existent set_headless method
• Assigning headless attribute directly
• Using add_option instead of add_argument

3. What will be the effect of the following Python Selenium code snippet?

from selenium import webdriver
options = webdriver.FirefoxOptions()
options.set_preference('dom.webnotifications.enabled', False)
driver = webdriver.Firefox(options=options)
driver.get('https://example.com')

medium

A. Code will raise an error due to invalid method

B. Firefox will launch but notifications will still appear

C. Firefox will launch with notifications disabled on the page

D. Firefox will launch in headless mode

Solution

1. Step 1: Understand set_preference usage

   The method set_preference sets Firefox preferences; here it disables web notifications.

2. Step 2: Analyze the effect on browser behavior

   Passing these options to Firefox disables notifications on pages, so no pop-ups appear.

3. Final Answer:

   Firefox will launch with notifications disabled on the page -> Option C

4. Quick Check:

   set_preference disables notifications [OK]

Hint: set_preference disables features like notifications [OK]

Common Mistakes:

• Assuming notifications still appear
• Confusing set_preference with add_argument
• Thinking code runs headless by default

4. Identify the error in this Selenium Python code snippet that tries to disable browser notifications in Chrome:

from selenium import webdriver
options = webdriver.ChromeOptions()
options.set_preference('profile.default_content_setting_values.notifications', 2)
driver = webdriver.Chrome(options=options)

medium

A. The value 2 is invalid for disabling notifications

B. set_preference is not a method of ChromeOptions

C. Options must be passed as capabilities, not options

D. ChromeOptions cannot disable notifications

Solution

1. Step 1: Check ChromeOptions methods

   ChromeOptions does not have a method called set_preference; this is Firefox-specific.

2. Step 2: Correct way to disable notifications in Chrome

   Chrome uses add_experimental_option with 'prefs' dictionary to disable notifications.

3. Final Answer:

   set_preference is not a method of ChromeOptions -> Option B

4. Quick Check:

   Use add_experimental_option for Chrome prefs [OK]

Hint: ChromeOptions uses add_experimental_option, not set_preference [OK]

Common Mistakes:

• Using Firefox methods on ChromeOptions
• Passing wrong values for notification settings
• Confusing options with capabilities

5. You want to run Chrome in headless mode, disable notifications, and accept insecure certificates using Selenium in Python. Which code snippet correctly sets all these options?

hard

A. options = webdriver.ChromeOptions()
options.headless = True
options.add_experimental_option('prefs', {'notifications': 0})
options.set_capability('acceptInsecureCerts', False)
driver = webdriver.Chrome(options=options)

B. options = webdriver.ChromeOptions()
options.add_argument('headless')
options.set_preference('notifications', False)
options.set_capability('acceptInsecureCerts', True)
driver = webdriver.Chrome(options=options)

C. options = webdriver.ChromeOptions()
options.add_argument('--headless')
options.add_argument('--disable-notifications')
options.accept_insecure_certs = True
driver = webdriver.Chrome(options=options)

D. options = webdriver.ChromeOptions()
options.add_argument('--headless')
options.add_experimental_option('prefs', {'profile.default_content_setting_values.notifications': 2})
options.set_capability('acceptInsecureCerts', True)
driver = webdriver.Chrome(options=options)

Solution

1. Step 1: Set headless mode correctly

   Use add_argument('--headless') to enable headless mode in ChromeOptions.

2. Step 2: Disable notifications properly

   Use add_experimental_option('prefs', {'profile.default_content_setting_values.notifications': 2}) to disable notifications.

3. Step 3: Accept insecure certificates

   Set capability acceptInsecureCerts to True using set_capability.

4. Final Answer:

   options = webdriver.ChromeOptions() options.add_argument('--headless') options.add_experimental_option('prefs', {'profile.default_content_setting_values.notifications': 2}) options.set_capability('acceptInsecureCerts', True) driver = webdriver.Chrome(options=options) -> Option D

5. Quick Check:

   Combine add_argument, add_experimental_option, set_capability [OK]

Hint: Use add_argument, add_experimental_option, set_capability together [OK]

Common Mistakes:

• Missing '--' in headless argument
• Using set_preference on ChromeOptions
• Setting acceptInsecureCerts to False by mistake