Screenshot on failure in Selenium Python - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

What is the output when the test fails and screenshot is taken?

Consider the following Selenium Python test snippet that tries to find a non-existing element and takes a screenshot on failure. What will be the output or result of running this code?

Selenium Python

from selenium import webdriver
from selenium.common.exceptions import NoSuchElementException

try:
    driver = webdriver.Chrome()
    driver.get('https://example.com')
    driver.find_element('id', 'nonexistent')
except NoSuchElementException:
    driver.save_screenshot('failure.png')
    print('Screenshot saved on failure')
finally:
    driver.quit()

A Raises TimeoutException

B Screenshot saved on failure

C No output, test passes silently

D SyntaxError due to wrong method call

💡 Hint

Look at the exception caught and what happens inside the except block.

The code tries to find an element that does not exist, which raises NoSuchElementException. The except block catches it, saves a screenshot, and prints a message. So the output is the printed message.

❓ assertion

intermediate

Which assertion correctly verifies screenshot file creation after failure?

After a test failure and screenshot capture, which assertion correctly checks that the screenshot file 'failure.png' exists?

Selenium Python

import os

# Assume screenshot is saved as 'failure.png' in current directory

# Which assertion below is correct?

A assert os.path.isfile('failure.png')

B assert os.path.exists('failure.png') == False

C assert os.path.isdir('failure.png')

D assert os.path.isfile('failure.png') == False

💡 Hint

Check which function verifies a file exists.

os.path.isfile returns True if the path exists and is a file. This is the correct way to assert the screenshot file was created.

🔧 Debug

advanced

Why does this screenshot code fail to save the image?

This Selenium Python code is supposed to save a screenshot on failure but does not create any file. What is the likely cause?

Selenium Python

from selenium import webdriver
from selenium.common.exceptions import NoSuchElementException

try:
    driver = webdriver.Chrome()
    driver.get('https://example.com')
    driver.find_element('id', 'nonexistent')
except NoSuchElementException:
    driver.save_screenshot()
    print('Screenshot saved')
finally:
    driver.quit()

A save_screenshot requires a filename argument, missing here

B NoSuchElementException is not caught properly

C driver.quit() is called before save_screenshot

D driver.get() URL is invalid

💡 Hint

Check the method call for saving screenshots.

The save_screenshot method needs a filename string argument to save the image. Without it, a TypeError is raised and no file is created.

❓ framework

advanced

How to integrate screenshot on failure in pytest with Selenium?

Which pytest fixture code snippet correctly captures a screenshot on test failure using Selenium WebDriver?

A

import pytest

def pytest_runtest_setup(item):
    driver.save_screenshot('failure.png')

B

import pytest

@pytest.fixture(autouse=True)
def screenshot_on_failure(request, driver):
    yield
    if request.node.rep_call.failed:
        driver.save_screenshot('failure.png')

C

import pytest

@pytest.hookimpl(hookwrapper=True)
def pytest_runtest_makereport(item, call):
    outcome = yield
    rep = outcome.get_result()
    if rep.when == 'call' and rep.failed:
        driver = item.funcargs['driver']
        driver.save_screenshot('failure.png')

D

import pytest

@pytest.fixture
def driver():
    driver = webdriver.Chrome()
    yield driver
    driver.save_screenshot('failure.png')
    driver.quit()

💡 Hint

Look for pytest hook that runs after test call and can access test result.

Option C uses pytest's hook wrapper pytest_runtest_makereport to check if the test failed and then saves a screenshot using the driver fixture.

🧠 Conceptual

expert

Why is taking screenshots on failure important in automated UI testing?

Select the best reason why automated UI tests should capture screenshots when they fail.

A Screenshots replace the need for logs and error messages

B Screenshots reduce test execution time significantly

C Screenshots prevent tests from failing by fixing bugs automatically

D Screenshots provide visual evidence of the UI state at failure, aiding debugging

💡 Hint

Think about how visual context helps when tests fail.

Screenshots show exactly what the user would see when the test failed, making it easier to understand and fix issues.

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