Browser console log capture in Selenium Python - Test Execution Trace

Test Overview

This test opens a web page using Selenium in Python, captures the browser console logs, and verifies that there are no severe errors in the logs.

Test Code - unittest

Selenium Python

from selenium import webdriver
from selenium.webdriver.chrome.service import Service
from selenium.webdriver.common.by import By
from selenium.webdriver.chrome.options import Options
import unittest

class TestBrowserConsoleLog(unittest.TestCase):
    def setUp(self):
        chrome_options = Options()
        chrome_options.set_capability('goog:loggingPrefs', {'browser': 'ALL'})
        self.driver = webdriver.Chrome(service=Service(), options=chrome_options)

    def test_console_log_no_severe_errors(self):
        self.driver.get('https://example.com')
        logs = self.driver.get_log('browser')
        severe_errors = [entry for entry in logs if entry['level'] == 'SEVERE']
        self.assertEqual(len(severe_errors), 0, f"Found severe errors in console logs: {severe_errors}")

    def tearDown(self):
        self.driver.quit()

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

Execution Trace - 6 Steps

Step	Action	System State	Assertion	Result
1	Test starts and Chrome browser is launched with logging preferences set to capture browser console logs	Chrome browser window opens with logging enabled for browser console	-	PASS
2	Navigates to https://example.com	Browser displays the Example Domain webpage	-	PASS
3	Retrieves browser console logs using driver.get_log('browser')	Console logs are collected as a list of log entries	-	PASS
4	Filters logs to find entries with level 'SEVERE'	Filtered list contains only severe error log entries (empty if none found)	Check that the number of severe errors is zero	PASS
5	Assertion checks that no severe errors exist in console logs	Test verifies no severe errors in browser console	assertEqual(len(severe_errors), 0)	PASS
6	Browser is closed and test ends	Browser window closes, resources cleaned up	-	PASS

Failure Scenario

Failing Condition: There are one or more severe errors in the browser console logs

Execution Trace Quiz - 3 Questions

What does the test check in the browser console logs?

A That the browser window is maximized

B That the page title is correct

C That there are no severe errors

D That the page contains a specific element

Key Result

Capturing and checking browser console logs helps catch JavaScript errors early, improving test reliability and debugging.