Grid architecture (hub and node) in Selenium Python - Test Execution Trace

Test Overview

This test connects to a Selenium Grid hub and runs a simple browser test on a node. It verifies that the page title is correct, confirming the grid setup works.

Test Code - Selenium

Selenium Python

from selenium import webdriver
from selenium.webdriver.common.desired_capabilities import DesiredCapabilities

# Connect to Selenium Grid Hub
hub_url = "http://localhost:4444/wd/hub"

# Use Chrome browser on the node
capabilities = DesiredCapabilities.CHROME.copy()

# Create remote WebDriver session
driver = webdriver.Remote(command_executor=hub_url, desired_capabilities=capabilities)

try:
    # Open example page
    driver.get("https://example.com")

    # Assert page title
    assert driver.title == "Example Domain", f"Expected title 'Example Domain' but got '{driver.title}'"

finally:
    driver.quit()

Execution Trace - 4 Steps

Step	Action	System State	Assertion	Result
1	Create Remote WebDriver session connecting to Selenium Grid hub at http://localhost:4444/wd/hub with Chrome capabilities	Selenium Grid hub is running and has at least one Chrome node registered	-	PASS
2	Browser on node opens and navigates to https://example.com	Browser window is open on the node, loading the example.com page	-	PASS
3	Check that the page title is exactly 'Example Domain'	Page is fully loaded with title 'Example Domain'	Assert driver.title == 'Example Domain'	PASS
4	Close the browser and end the session	Browser window is closed, session terminated	-	PASS

Failure Scenario

Failing Condition: Selenium Grid hub is not running or no nodes are available, or page title does not match expected

Execution Trace Quiz - 3 Questions

What does the Remote WebDriver connect to in Selenium Grid architecture?

A Directly to the browser on the node

B The local machine's browser

C The Selenium Grid hub URL

D The test script file

Key Result

Always verify that the Selenium Grid hub and nodes are running and properly registered before running tests. This ensures your remote sessions can start and tests execute on the intended browsers.