Full page screenshot in Selenium Python - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a full page screenshot in web testing?

A full page screenshot captures the entire webpage from top to bottom, including parts not visible on the screen without scrolling.

beginner

Why is a full page screenshot useful in testing?

It helps verify the complete layout and content of a webpage, catching visual bugs that appear outside the visible screen area.

beginner

Which Selenium Python method is commonly used to take a screenshot?

The method is driver.save_screenshot('filename.png'), but it captures only the visible part of the page by default.

intermediate

How can you capture a full page screenshot using Selenium in Python?

You can use the Chrome DevTools Protocol (CDP) commands via Selenium to capture full page screenshots or use third-party libraries that stitch multiple screenshots.

intermediate

What is a common challenge when taking full page screenshots with Selenium?

Selenium's default screenshot captures only the visible viewport, so capturing the entire page requires extra steps like scrolling or using browser-specific commands.

What does a full page screenshot capture?

A Only the visible part of the webpage

B Only the footer section

C Only the header section

D The entire webpage including off-screen parts

A full page screenshot captures the entire webpage, including parts not visible without scrolling.

Which Selenium Python method captures a screenshot of the visible page?

A driver.save_screenshot('file.png')

B driver.full_screenshot()

C driver.get_screenshot_as_base64()

D driver.capture_full_page()

driver.save_screenshot('file.png') captures the visible part of the page as an image file.

What extra step is often needed to capture a full page screenshot with Selenium?

A Using driver.close()

B Clearing browser cache

C Scrolling and stitching multiple screenshots

D Maximizing the browser window

Because Selenium captures only the visible viewport, scrolling and stitching screenshots is a common method to get the full page.

Which browser feature can Selenium use to capture full page screenshots more easily?

A Chrome DevTools Protocol (CDP)

B Browser history

C Cookies management

D Incognito mode

Chrome DevTools Protocol allows commands to capture full page screenshots directly.

Why might a full page screenshot be better than a visible viewport screenshot in testing?

A It loads faster

B It shows all page content, catching hidden bugs

C It uses less memory

D It requires no code

Full page screenshots show all content, helping find bugs outside the visible area.

Explain how to capture a full page screenshot using Selenium in Python.

Think about how Selenium normally captures screenshots and what extra steps are needed for full page.

Why is capturing a full page screenshot important in web testing?

Consider what might be missed if only the visible part is captured.

Practice

1. What is the main advantage of taking a full page screenshot in Selenium?

easy

A. It speeds up the test execution

B. It only captures the visible part of the webpage

C. It captures the entire webpage, including parts not visible on screen

D. It automatically scrolls the page during testing

Solution

1. Step 1: Understand what a full page screenshot means

   A full page screenshot captures the entire webpage, not just the visible part on the screen.

2. Step 2: Compare options with this definition

   Only It captures the entire webpage, including parts not visible on screen correctly states this advantage. Options B, C, and D describe other unrelated behaviors.

3. Final Answer:

   It captures the entire webpage, including parts not visible on screen -> Option C

4. Quick Check:

   Full page screenshot = entire page capture [OK]

Hint: Full page means entire webpage, not just visible part [OK]

Common Mistakes:

• Confusing full page with visible viewport only
• Thinking it speeds up tests automatically
• Assuming it scrolls the page during capture

2. Which Selenium Python method is used to save a full page screenshot in Firefox?

easy

A. driver.get_screenshot_as_file('file.png')

B. driver.save_full_page_screenshot('file.png')

C. driver.save_screenshot('file.png')

D. driver.take_full_screenshot('file.png')

Solution

1. Step 1: Identify the correct method for full page screenshot in Firefox

   Firefox does not have a built-in method named save_full_page_screenshot. The standard method to save a screenshot is get_screenshot_as_file, which captures the visible viewport.

2. Step 2: Check other options for correctness

   driver.save_full_page_screenshot('file.png') is invalid as save_full_page_screenshot is not a standard Selenium method. driver.save_screenshot('file.png') saves visible viewport screenshot. driver.take_full_screenshot('file.png') is not a valid method.

3. Final Answer:

   driver.get_screenshot_as_file('file.png') -> Option A

4. Quick Check:

   Standard screenshot method = get_screenshot_as_file [OK]

Hint: Use get_screenshot_as_file to save screenshot [OK]

Common Mistakes:

• Using non-existent save_full_page_screenshot method
• Confusing save_screenshot with full page capture
• Trying invalid methods like take_full_screenshot

3. Given this code snippet, what will be the result?

driver.get('https://example.com')
driver.save_full_page_screenshot('page.png')
print('Screenshot saved')

medium

A. Runtime error because get_full_page_screenshot_as_file is unsupported

B. Screenshot saved and full page screenshot saved as 'page.png'

C. Only visible part screenshot saved as 'page.png'

D. SyntaxError due to incorrect method name

Solution

1. Step 1: Analyze the method usage

   The method save_full_page_screenshot is not a valid Selenium WebDriver method and will cause a SyntaxError or AttributeError.

2. Step 2: Check the print statement

   The print statement will not execute because the previous line causes an error.

3. Final Answer:

   SyntaxError due to incorrect method name -> Option D

4. Quick Check:

   Invalid method call causes error [OK]

Hint: Invalid method names cause errors [OK]

Common Mistakes:

• Assuming method is supported causing success
• Confusing full page with visible screenshot
• Thinking method name is correct syntax

4. You wrote this code but get a blank screenshot file:

driver.get('https://example.com')
driver.save_screenshot('screen.png')

What is the likely cause?

medium

A. Page did not fully load before screenshot

B. save_screenshot does not save files

C. Method get_full_page_screenshot_as_file is required instead

D. Screenshot file path is invalid

Solution

1. Step 1: Understand why screenshot is blank

   If the page is not fully loaded, the screenshot may capture a blank or incomplete page.

2. Step 2: Evaluate other options

   save_screenshot does save files. Method get_full_page_screenshot_as_file is unrelated to blank screenshot issue. Invalid file path would cause an error, not a blank file.

3. Final Answer:

   Page did not fully load before screenshot -> Option A

4. Quick Check:

   Wait for page load before screenshot [OK]

Hint: Always wait for page load before screenshot [OK]

Common Mistakes:

• Assuming save_screenshot never saves files
• Confusing full page screenshot with blank image issue
• Ignoring page load timing problems

5. How can you ensure a clean full page screenshot in headless Firefox using Selenium Python?

hard

A. Use save_screenshot immediately after driver.get() without waits

B. Scroll manually and take multiple viewport screenshots

C. Use headless mode, wait for page load, then call save_full_page_screenshot

D. Use driver.execute_script to hide elements before screenshot

Solution

1. Step 1: Understand headless mode limitations

   Headless Firefox does not support a built-in full page screenshot method.

2. Step 2: Use manual scrolling and multiple viewport screenshots

   To capture the full page, scroll manually and stitch multiple viewport screenshots.

3. Final Answer:

   Scroll manually and take multiple viewport screenshots -> Option B

4. Quick Check:

   Manual scroll + multiple screenshots = full page capture [OK]

Hint: Manual scrolling needed for full page in headless Firefox [OK]

Common Mistakes:

• Assuming save_full_page_screenshot exists in headless mode
• Taking screenshot immediately without waiting
• Hiding elements unnecessarily before capture