Grid setup and configuration in Selenium Python - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to connect to the Selenium Grid hub.

Selenium Python

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

hub = webdriver.Remote(command_executor='http://localhost:4444/wd/hub', desired_capabilities=[1])

hub.quit()

Drag options to blanks, or click blank then click option'

ADesiredCapabilities.FIREFOX

BDesiredCapabilities.SAFARI

CDesiredCapabilities.CHROME

DDesiredCapabilities.EDGE

Attempts:

3 left

💡 Hint

Common Mistakes

Using a wrong DesiredCapabilities value that does not match the node's browser.

Forgetting to specify desired_capabilities parameter.

The hub needs to know which browser capabilities to use. Here, we use DesiredCapabilities.CHROME to specify Chrome browser.

2fill in blank

medium

Complete the code to register a node to the Selenium Grid hub using command line.

Selenium Python

java -jar selenium-server-standalone.jar -role node -hub http://localhost:4444/grid/register -port [1]

Drag options to blanks, or click blank then click option'

A5555

B4444

C8080

D5554

Attempts:

3 left

💡 Hint

Common Mistakes

Using the same port as the hub (4444) for the node.

Choosing a port that is already in use.

The node must run on a different port than the hub. Port 5555 is commonly used for nodes.

3fill in blank

hard

Fix the error in the node configuration JSON to specify the correct browser name.

Selenium Python

{
  "capabilities": [
    {
      "browserName": "[1]",
      "maxInstances": 5
    }
  ],
  "configuration": {
    "port": 5555,
    "hub": "http://localhost:4444/grid/register"
  }
}

Drag options to blanks, or click blank then click option'

Ainternet explorer

Bchrome

Cfirefox

Dsafari

Attempts:

3 left

💡 Hint

Common Mistakes

Using uppercase or incorrect browser names.

Using browser names that do not match installed browsers on the node.

The browserName must be lowercase and match the browser the node supports. "chrome" is the correct value for Chrome browser.

4fill in blank

hard

Fill both blanks to create a Python test that connects to the Selenium Grid hub and opens a webpage.

Selenium Python

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

browser = webdriver.Remote(command_executor='http://localhost:4444/wd/hub', desired_capabilities=[1])
browser.get([2])
browser.quit()

Drag options to blanks, or click blank then click option'

ADesiredCapabilities.FIREFOX

B"https://example.com"

CDesiredCapabilities.CHROME

D"http://localhost"

Attempts:

3 left

💡 Hint

Common Mistakes

Mixing browser capabilities and URL values.

Forgetting to put quotes around the URL.

Use DesiredCapabilities.CHROME to specify Chrome browser and open the URL https://example.com.

5fill in blank

hard

Fill all three blanks to create a Python dictionary comprehension that filters nodes by maxInstances and browserName.

Selenium Python

filtered_nodes = {node['id']: node for node in nodes if node['maxInstances'] [1] 3 and node['browserName'] == [2] and node['status'] == [3]

Drag options to blanks, or click blank then click option'

A>

B"chrome"

C"active"

D<

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong comparison operators like < instead of >.

Forgetting quotes around string values.

Mixing up the order of conditions.

The comprehension filters nodes with maxInstances greater than 3, browserName equal to "chrome", and status equal to "active".

Practice

1. What is the main purpose of Selenium Grid in test automation?

easy

A. To generate test reports automatically

B. To run tests on multiple browsers and machines simultaneously

C. To debug test scripts locally

D. To write test scripts faster

Solution

1. Step 1: Understand Selenium Grid's role

   Selenium Grid allows running tests on different browsers and machines at the same time to save time and increase coverage.

2. Step 2: Compare options with Grid's purpose

   Only To run tests on multiple browsers and machines simultaneously describes running tests on multiple browsers and machines simultaneously, which is the core feature of Selenium Grid.

3. Final Answer:

   To run tests on multiple browsers and machines simultaneously -> Option B

4. Quick Check:

   Selenium Grid = Run tests on many browsers/machines [OK]

Hint: Remember Grid = multiple browsers + machines running tests [OK]

Common Mistakes:

• Confusing Grid with test script writing tools
• Thinking Grid generates reports
• Assuming Grid is for debugging only

2. Which Python code snippet correctly creates a Remote WebDriver to connect to a Selenium Grid hub at 'http://localhost:4444/wd/hub' for Chrome browser?

easy

A. driver = webdriver.Remote(command_executor='http://localhost:4444/wd/hub', desired_capabilities={'browserName': 'chrome'})

B. driver = webdriver.Chrome('http://localhost:4444/wd/hub')

C. driver = webdriver.Remote('chrome', 'http://localhost:4444/wd/hub')

D. driver = webdriver.Remote('http://localhost:4444/wd/hub', browser='chrome')

Solution

1. Step 1: Check Remote WebDriver syntax

   webdriver.Remote requires 'command_executor' URL and 'desired_capabilities' dictionary specifying browser.

2. Step 2: Validate each option

   driver = webdriver.Remote(command_executor='http://localhost:4444/wd/hub', desired_capabilities={'browserName': 'chrome'}) correctly uses command_executor and desired_capabilities with browserName 'chrome'. Others misuse parameters or classes.

3. Final Answer:

   driver = webdriver.Remote(command_executor='http://localhost:4444/wd/hub', desired_capabilities={'browserName': 'chrome'}) -> Option A

4. Quick Check:

   Remote WebDriver needs command_executor + desired_capabilities [OK]

Hint: Use command_executor and desired_capabilities keys for Remote [OK]

Common Mistakes:

• Using webdriver.Chrome instead of webdriver.Remote
• Passing URL as first argument without keyword
• Incorrect parameter names like 'browser' instead of 'desired_capabilities'

3. Given this Python code connecting to Selenium Grid:

from selenium import webdriver
caps = {'browserName': 'firefox'}
driver = webdriver.Remote(command_executor='http://localhost:4444/wd/hub', desired_capabilities=caps)
driver.get('https://example.com')
print(driver.title)

What will be printed if the Grid and node are correctly set up?

medium

A. Empty string

B. An error about missing local browser

C. The title of the page at https://example.com

D. SyntaxError

Solution

1. Step 1: Understand code execution with Grid

   The code uses Remote WebDriver to open Firefox on Grid node and navigates to example.com.

2. Step 2: Predict output of print(driver.title)

   If Grid and node are correct, driver.title returns the page title of example.com, which is a string like 'Example Domain'.

3. Final Answer:

   The title of the page at https://example.com -> Option C

4. Quick Check:

   Remote driver prints page title when setup is correct [OK]

Hint: Correct Grid setup means driver.title shows page title [OK]

Common Mistakes:

• Expecting local browser errors when Grid is correct
• Thinking driver.title returns empty string by default
• Confusing syntax errors with runtime behavior

4. You wrote this code to connect to Selenium Grid but get a connection error:

driver = webdriver.Remote('http://localhost:4444/wd/hub', {'browserName': 'chrome'})

What is the likely cause and how to fix it?

medium

A. Missing keyword arguments; use command_executor and desired_capabilities keywords

B. Wrong URL; should be 'http://localhost:5555/wd/hub'

C. Browser name must be uppercase 'Chrome'

D. webdriver.Remote does not support Chrome browser

Solution

1. Step 1: Identify correct webdriver.Remote syntax

   webdriver.Remote requires keyword arguments: command_executor for URL and desired_capabilities for browser info.

2. Step 2: Analyze given code

   Code passes URL and capabilities as positional arguments without keywords, causing connection error.

3. Final Answer:

   Missing keyword arguments; use command_executor and desired_capabilities keywords -> Option A

4. Quick Check:

   webdriver.Remote needs command_executor and desired_capabilities keywords [OK]

Hint: Always use command_executor and desired_capabilities keywords [OK]

Common Mistakes:

• Passing URL and capabilities as positional args
• Changing URL port without reason
• Incorrect browser name casing

5. You want to run tests on both Chrome and Firefox browsers using Selenium Grid. Which approach correctly sets up the test to run on both browsers sequentially using Python?

hard

A. Create one Remote WebDriver with both browser names in desired_capabilities at once

B. Start two Grid hubs, one for Chrome and one for Firefox, and connect separately

C. Run tests locally on Chrome and Firefox without Grid

D. Use a loop over a list of desired capabilities and create a Remote WebDriver for each browser inside the loop

Solution

1. Step 1: Understand how to run tests on multiple browsers with Grid

   Each Remote WebDriver instance connects to one browser session. To test multiple browsers, create separate instances.

2. Step 2: Evaluate options

   Use a loop over a list of desired capabilities and create a Remote WebDriver for each browser inside the loop correctly uses a loop to create Remote WebDriver for each browser sequentially. Create one Remote WebDriver with both browser names in desired_capabilities at once is invalid because desired_capabilities cannot hold multiple browsers at once.

3. Final Answer:

   Use a loop over a list of desired capabilities and create a Remote WebDriver for each browser inside the loop -> Option D

4. Quick Check:

   Loop over browsers, create Remote driver each time [OK]

Hint: Loop browsers, create Remote driver per browser session [OK]

Common Mistakes:

• Trying to set multiple browsers in one desired_capabilities dict
• Running tests locally instead of using Grid
• Starting multiple hubs unnecessarily