Screenshot on failure in Selenium Python - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the purpose of taking a screenshot on test failure in Selenium?

Taking a screenshot on test failure helps to capture the exact state of the web page when the test failed. This makes it easier to understand what went wrong and debug the issue.

beginner

Which Selenium WebDriver method is used to capture a screenshot in Python?

The method driver.save_screenshot('filename.png') is used to capture and save a screenshot of the current browser window.

intermediate

How can you automatically take a screenshot only when a test fails in Python unittest?

You can override the tearDown method to check if the test failed, and if so, call driver.save_screenshot() to save the screenshot.

beginner

Why is it important to name screenshot files with timestamps or test names?

Naming screenshots with timestamps or test names prevents overwriting files and helps quickly identify which test and time the screenshot belongs to.

intermediate

What is a simple way to integrate screenshot capture on failure in pytest?

In pytest, you can use the request.node.rep_call.failed hook in a fixture to detect failure and then call driver.save_screenshot() to save the screenshot.

Which Selenium WebDriver method saves a screenshot in Python?

A get_screenshot()

B take_screenshot()

C capture_screen()

D save_screenshot()

The correct method is save_screenshot() which saves the current browser window as an image file.

When should you take a screenshot during automated testing?

A Only when the test fails

B Before starting the test

C Only when the test passes

D After every test step

Taking screenshots on failure helps capture the error state for debugging.

In unittest, which method is best to override to add screenshot capture on failure?

A tearDown()

B setUp()

C runTest()

D startTest()

The tearDown() method runs after each test and is ideal to check for failure and capture screenshots.

Why add timestamps to screenshot filenames?

A To make files smaller

B To prevent overwriting and identify when the screenshot was taken

C To encrypt the file

D To improve screenshot quality

Timestamps help avoid overwriting files and make it easier to track when the screenshot was taken.

Which Python testing framework allows using fixtures to capture screenshots on failure?

A unittest

B nose

C pytest

D doctest

pytest supports fixtures that can detect test failure and capture screenshots automatically.

Explain how to implement automatic screenshot capture on test failure using Selenium with Python unittest.

Think about what happens after each test and how to detect failure.

Describe best practices for naming and storing screenshots taken on test failure.

Consider how to keep screenshots easy to find and identify.

Practice

1. What is the main purpose of taking a screenshot on test failure in Selenium?

easy

A. To capture the current state of the web page for debugging

B. To speed up the test execution

C. To improve the browser's performance

D. To automatically fix the test errors

Solution

1. Step 1: Understand the role of screenshots in testing

   Screenshots help testers see what the user saw when the test failed.

2. Step 2: Identify the purpose of capturing screenshots on failure

   They provide visual evidence to debug UI problems quickly.

3. Final Answer:

   To capture the current state of the web page for debugging -> Option A

4. Quick Check:

   Screenshot on failure = capture page state [OK]

Hint: Screenshots show what failed looks like visually [OK]

Common Mistakes:

• Thinking screenshots speed up tests
• Believing screenshots fix errors automatically
• Confusing screenshots with performance tools

2. Which of the following is the correct syntax to take a screenshot in Selenium Python when a test fails?

easy

A. driver.save_screenshot('error.png')

B. driver.takeScreenshot('error.png')

C. driver.capture('error.png')

D. driver.screenshotSave('error.png')

Solution

1. Step 1: Recall Selenium Python screenshot method

   The correct method to save a screenshot is save_screenshot().

2. Step 2: Verify method names and syntax

   Only driver.save_screenshot('error.png') matches Selenium's API.

3. Final Answer:

   driver.save_screenshot('error.png') -> Option A

4. Quick Check:

   Correct method name = save_screenshot [OK]

Hint: Remember method is save_screenshot with underscore [OK]

Common Mistakes:

• Using camelCase instead of snake_case
• Using non-existent methods like capture or screenshotSave
• Missing parentheses or quotes

3. What will be the output if the following Selenium Python code runs and the element is not found?

try:
    driver.find_element(By.ID, 'submit').click()
except Exception as e:
    driver.save_screenshot('fail.png')
    print('Screenshot saved on failure')

medium

A. No output, test passes silently

B. RuntimeError without screenshot

C. SyntaxError due to missing import

D. Screenshot saved on failure

Solution

1. Step 1: Analyze try-except behavior on element not found

   If element is missing, exception triggers except block.

2. Step 2: Check actions in except block

   Screenshot is saved and message printed: 'Screenshot saved on failure'.

3. Final Answer:

   Screenshot saved on failure -> Option D

4. Quick Check:

   Exception triggers screenshot and print [OK]

Hint: Exception triggers except block actions [OK]

Common Mistakes:

• Assuming test passes silently on failure
• Confusing syntax errors with runtime exceptions
• Ignoring the print statement inside except

4. Identify the error in this Selenium Python snippet intended to save a screenshot on failure:

try:
    driver.find_element(By.NAME, 'login').click()
except:
    driver.save_screenshot(failure.png)

medium

A. No error, code is correct

B. Incorrect exception handling syntax

C. Missing quotes around filename in save_screenshot

D. Wrong method name saveScreenshot instead of save_screenshot

Solution

1. Step 1: Check save_screenshot argument syntax

   Filename must be a string in quotes, but here it is unquoted.

2. Step 2: Confirm exception handling and method name

   Except syntax and method name are correct; only filename is wrong.

3. Final Answer:

   Missing quotes around filename in save_screenshot -> Option C

4. Quick Check:

   Filename must be a string in quotes [OK]

Hint: Always put filename in quotes for save_screenshot [OK]

Common Mistakes:

• Forgetting quotes around filename string
• Changing method name incorrectly
• Misusing except syntax

5. You want to automatically take a screenshot only when a Selenium test fails and save it with a timestamp. Which approach below correctly implements this in Python?

hard

A. Use driver.save_screenshot('fail.png') outside try-except block

B. Use try-except around test steps, call driver.save_screenshot(f"fail_{time.time()}.png") in except

C. Call driver.save_screenshot() before every test step unconditionally

D. Use a loop to retry test steps and save screenshot on success

Solution

1. Step 1: Understand when to take screenshots

   Screenshots should be taken only on failure, inside except block.

2. Step 2: Use timestamp for unique filenames

   Using time.time() in filename ensures unique screenshot names.

3. Final Answer:

   Use try-except around test steps, call driver.save_screenshot(f"fail_{time.time()}.png") in except -> Option B

4. Quick Check:

   Screenshot on failure with timestamp = try-except + formatted filename [OK]

Hint: Take screenshots only in except block with timestamped names [OK]

Common Mistakes:

• Taking screenshots before test steps always
• Saving screenshots outside exception handling
• Retrying tests without capturing failure screenshots