Logging setup in Selenium Python

Introduction

Logging helps you keep track of what your Selenium tests are doing. It records important events and errors so you can understand what happened during a test.

When you want to see what steps your Selenium test performed.

When you need to find out why a test failed by checking error messages.

When you want to save test results and events for later review.

When running tests on a remote machine and cannot watch the browser directly.

When debugging complex test flows to understand the sequence of actions.

Syntax

Selenium Python

import logging

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

logging.info('This is an info message')
logging.error('This is an error message')

logging.basicConfig sets up the logging system with a level and format.

The level controls which messages are shown (INFO, ERROR, DEBUG, etc.).

Examples

This example shows how to log debug and info messages. Debug messages appear because the level is set to DEBUG.

Selenium Python

import logging

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

This example saves warning and error messages to a file named test.log.

Selenium Python

import logging

logging.basicConfig(filename='test.log', level=logging.WARNING)
logging.warning('Warning message')
logging.error('Error message')

This example changes the log message format to show only the level and message.

Selenium Python

import logging

logging.basicConfig(format='%(levelname)s: %(message)s')
logging.info('Info message')

Sample Program

This program sets up logging to show info messages with timestamps. It runs a simple Selenium test that opens a website, finds a heading, logs the text, and handles errors.

Selenium Python

import logging
from selenium import webdriver
from selenium.webdriver.common.by import By

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

logging.info('Starting the Selenium test')

# Setup Chrome driver
options = webdriver.ChromeOptions()
options.add_argument('--headless')
driver = webdriver.Chrome(options=options)

try:
    driver.get('https://example.com')
    logging.info('Opened example.com')
    element = driver.find_element(By.TAG_NAME, 'h1')
    logging.info(f'Found heading: {element.text}')
except Exception as e:
    logging.error(f'Error during test: {e}')
finally:
    driver.quit()
    logging.info('Closed the browser')

Important Notes

Use logging.error() to record problems that need attention.

Set the logging level to DEBUG for detailed messages during development.

Logging to a file helps keep records when running tests automatically.

Summary

Logging records important events and errors during Selenium tests.

Use logging.basicConfig() to set up logging level and format.

Logs help you understand test behavior and find problems quickly.

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