Logging setup in Selenium Python - Build an Automation Script

Verify logging setup captures test execution details

Preconditions (2)

Step 1: Configure logging to write INFO level messages to a file named 'test.log'

Step 2: Start the Selenium WebDriver for Chrome

Step 3: Log the message 'Test started' before opening the webpage

Step 4: Navigate to 'https://example.com'

Step 5: Log the message 'Page opened successfully' after navigation

Step 6: Close the browser

Step 7: Log the message 'Test finished' after closing the browser

Step 8: Check the 'test.log' file for the logged messages

✅ Expected Result: The 'test.log' file contains the messages: 'Test started', 'Page opened successfully', and 'Test finished' in order

Automation Requirements - selenium with python unittest

Assertions Needed:

Verify the 'test.log' file exists after test execution

Verify the 'test.log' file contains the expected log messages in correct order

Best Practices:

Use Python's built-in logging module with proper configuration

Use explicit waits if needed (not required here as page is simple)

Use unittest framework for structuring the test

Ensure WebDriver is properly closed in tearDown method

Use assertions to verify log file content

Automated Solution

Selenium Python

import unittest
import logging
import os
from selenium import webdriver
from selenium.webdriver.chrome.service import Service
from selenium.webdriver.chrome.options import Options

class TestLoggingSetup(unittest.TestCase):
    @classmethod
    def setUpClass(cls):
        # Configure logging
        logging.basicConfig(
            filename='test.log',
            level=logging.INFO,
            format='%(asctime)s - %(levelname)s - %(message)s',
            filemode='w'
        )

    def setUp(self):
        chrome_options = Options()
        chrome_options.add_argument('--headless')  # Run headless for test automation
        service = Service()
        self.driver = webdriver.Chrome(service=service, options=chrome_options)

    def test_logging(self):
        logging.info('Test started')
        self.driver.get('https://example.com')
        logging.info('Page opened successfully')
        self.assertIn('Example Domain', self.driver.title)

    def tearDown(self):
        self.driver.quit()
        logging.info('Test finished')

    @classmethod
    def tearDownClass(cls):
        # Verify log file content
        assert os.path.exists('test.log'), 'Log file does not exist'
        with open('test.log', 'r') as f:
            log_content = f.read()
        assert 'Test started' in log_content, 'Missing "Test started" log'
        assert 'Page opened successfully' in log_content, 'Missing "Page opened successfully" log'
        assert 'Test finished' in log_content, 'Missing "Test finished" log'

if __name__ == '__main__':
    unittest.main()

This test script uses Python's unittest framework to organize the test.

In setUpClass, logging is configured to write INFO level messages to test.log with timestamps.

The setUp method starts a headless Chrome browser for automation.

The test method logs 'Test started', opens the webpage, logs 'Page opened successfully', and asserts the page title contains 'Example Domain' to confirm navigation.

The tearDown method closes the browser and logs 'Test finished'.

Finally, tearDownClass verifies the log file exists and contains all expected messages in order.

This structure ensures logging captures key test steps and the test verifies the logging output as expected.

Common Mistakes - 4 Pitfalls

{'mistake': 'Not configuring logging before test starts', 'why_bad': "Logging messages won't be recorded if logging is not set up properly before usage.", 'correct_approach': 'Configure logging in setUpClass or before any logging calls.'}

Not closing the WebDriver properly

{'mistake': 'Checking log file content without ensuring file is flushed and closed', 'why_bad': 'Log messages might not be written yet, causing false test failures.', 'correct_approach': "Configure logging with filemode='w' and verify after test finishes."}

Hardcoding absolute paths for log file

Bonus Challenge

Now add data-driven testing with 3 different URLs and verify logging for each

Show Hint

Practice

1. What is the main purpose of setting up logging in Selenium Python tests?

easy

A. To record important events and errors during test execution

B. To speed up the test execution time

C. To automatically fix errors in the test code

D. To generate HTML reports of test results

Solution

1. Step 1: Understand logging purpose

   Logging is used to keep track of events and errors that happen during tests.

2. Step 2: Compare options

   Only recording events and errors matches logging's main role; speeding up or fixing code is unrelated.

3. Final Answer:

   To record important events and errors during test execution -> Option A

4. Quick Check:

   Logging = Record events/errors [OK]

Hint: Logging records events and errors, not speeds or fixes [OK]

Common Mistakes:

• Thinking logging speeds up tests
• Confusing logging with test fixing tools
• Assuming logging creates reports automatically

2. Which of the following is the correct way to set the logging level to DEBUG in Selenium Python?

easy

A. logging.config(level='DEBUG')

B. logging.setLevel(DEBUG)

C. logging.basicConfig(level=logging.DEBUG)

D. logging.start(level=logging.DEBUG)

Solution

1. Step 1: Recall logging setup syntax

   Use logging.basicConfig() with level=logging.DEBUG to set debug level.

2. Step 2: Validate options

   Only logging.basicConfig(level=logging.DEBUG) uses correct function and syntax; others are invalid or incorrect method calls.

3. Final Answer:

   logging.basicConfig(level=logging.DEBUG) -> Option C

4. Quick Check:

   basicConfig + level=logging.DEBUG = Correct [OK]

Hint: Use logging.basicConfig(level=logging.DEBUG) to set debug level [OK]

Common Mistakes:

• Using logging.setLevel instead of basicConfig
• Passing level as string without logging prefix
• Calling non-existent logging.start() method

3. What will be the output when running this code snippet?

import logging
logging.basicConfig(level=logging.INFO)
logging.debug('Debug message')
logging.info('Info message')

medium

A. No output

B. Debug message\nInfo message

C. Debug message

D. Info message

Solution

1. Step 1: Understand logging level effect

   Setting level to INFO means messages below INFO (like DEBUG) are ignored.

2. Step 2: Check which messages print

   DEBUG message is ignored; INFO message is printed.

3. Final Answer:

   Info message -> Option D

4. Quick Check:

   Level INFO hides DEBUG, shows INFO [OK]

Hint: Messages below set level do not appear in output [OK]

Common Mistakes:

• Expecting DEBUG messages to show at INFO level
• Confusing logging levels order
• Assuming all messages print regardless of level

4. Identify the error in this logging setup code:

import logging
logging.basicConfig(level='DEBUG')
logging.debug('Test message')

medium

A. logging.debug() cannot be called before configuring logging

B. The level argument should be an integer, not a string

C. logging.basicConfig() requires a filename argument

D. There is no error; the code runs correctly

Solution

1. Step 1: Check logging.basicConfig level argument type

   The level argument must be a logging level constant like logging.DEBUG, not a string.

2. Step 2: Validate other options

   logging.debug() can be called after basicConfig; filename is optional; code errors due to string level.

3. Final Answer:

   The level argument should be an integer, not a string -> Option B

4. Quick Check:

   Level must be logging.DEBUG, not 'DEBUG' string [OK]

Hint: Use logging.DEBUG constant, not 'DEBUG' string for level [OK]

Common Mistakes:

• Passing level as string instead of logging constant
• Thinking filename is mandatory in basicConfig
• Calling logging.debug before configuration causes error

5. You want to log Selenium test events to a file named test.log with timestamps and message levels. Which code snippet correctly sets this up?

hard

A. logging.basicConfig(filename='test.log', level=logging.INFO, format='%(asctime)s - %(levelname)s - %(message)s')

B. logging.basicConfig(file='test.log', level='INFO', format='%(time)s - %(level)s - %(msg)s')

C. logging.setup(filename='test.log', level=logging.INFO, format='%(asctime)s - %(levelname)s - %(message)s')

D. logging.basicConfig(filename='test.log', level=logging.DEBUG, format='%(message)s')

Solution

1. Step 1: Identify correct parameters for file logging

   Use filename='test.log', level=logging.INFO, and correct format string with asctime and levelname.

2. Step 2: Check each option for correctness

   logging.basicConfig(filename='test.log', level=logging.INFO, format='%(asctime)s - %(levelname)s - %(message)s') uses correct parameter names and format; A uses wrong keys and strings; C uses non-existent logging.setup; D misses timestamps and uses DEBUG level.

3. Final Answer:

   logging.basicConfig(filename='test.log', level=logging.INFO, format='%(asctime)s - %(levelname)s - %(message)s') -> Option A

4. Quick Check:

   filename + level=logging.INFO + correct format = logging.basicConfig(filename='test.log', level=logging.INFO, format='%(asctime)s - %(levelname)s - %(message)s') [OK]

Hint: Use filename, level=logging.INFO, and format with %(asctime)s [OK]

Common Mistakes:

• Using wrong parameter names like file instead of filename
• Passing level as string instead of logging constant
• Missing timestamp in format string