Selenium Grid setup in Selenium Java - Build an Automation Script

Verify Selenium Grid setup with remote WebDriver

Preconditions (2)

Step 1: Create a RemoteWebDriver instance connecting to the Selenium Grid Hub URL

Step 2: Set desired capabilities for Chrome browser

Step 3: Navigate to https://www.example.com

Step 4: Verify the page title is 'Example Domain'

Step 5: Close the browser session

✅ Expected Result: The test should open Chrome browser on the remote node via Selenium Grid, load the example.com page, verify the title matches 'Example Domain', and close the browser without errors.

Automation Requirements - Selenium WebDriver with TestNG

Assertions Needed:

Assert that the page title equals 'Example Domain'

Best Practices:

Use explicit waits if needed

Use DesiredCapabilities or ChromeOptions properly

Handle exceptions and ensure driver quits in finally block

Use proper locator strategies if interacting with elements (not needed here)

Use TestNG annotations for setup and teardown

Automated Solution

Selenium Java

import org.openqa.selenium.WebDriver;
import org.openqa.selenium.remote.RemoteWebDriver;
import org.openqa.selenium.chrome.ChromeOptions;
import org.testng.annotations.AfterClass;
import org.testng.annotations.BeforeClass;
import org.testng.annotations.Test;
import java.net.URL;
import static org.testng.Assert.assertEquals;

public class SeleniumGridTest {
    private WebDriver driver;

    @BeforeClass
    public void setUp() throws Exception {
        ChromeOptions options = new ChromeOptions();
        // Connect to Selenium Grid Hub
        driver = new RemoteWebDriver(new URL("http://localhost:4444/wd/hub"), options);
    }

    @Test
    public void testExampleDotComTitle() {
        driver.get("https://www.example.com");
        String title = driver.getTitle();
        assertEquals(title, "Example Domain", "Page title should be 'Example Domain'");
    }

    @AfterClass
    public void tearDown() {
        if (driver != null) {
            driver.quit();
        }
    }
}

The @BeforeClass method sets up the RemoteWebDriver to connect to the Selenium Grid Hub URL with ChromeOptions, which tells Selenium to use Chrome browser on a remote node.

The @Test method navigates to https://www.example.com and asserts the page title is exactly 'Example Domain'. This verifies the remote browser is working correctly.

The @AfterClass method ensures the browser session is closed properly to free resources.

This structure uses TestNG annotations for clear setup, test, and teardown phases, following best practices for Selenium Grid tests.

Common Mistakes - 4 Pitfalls

Hardcoding local WebDriver instead of RemoteWebDriver

Not specifying browser options or capabilities

Not handling exceptions or failing to quit driver

Using incorrect Hub URL or missing /wd/hub suffix

Bonus Challenge

Now add data-driven testing to run the same test on Chrome and Firefox browsers via Selenium Grid.

Show Hint

Practice

1. What is the primary role of the Selenium Grid Hub in a test setup?

easy

A. To create test data for automation

B. To execute test scripts locally on the machine

C. To manage and distribute test requests to connected Nodes

D. To store test results and logs

Solution

1. Step 1: Understand the Hub's function

   The Hub acts as a central point that receives test requests and sends them to the appropriate Nodes.

2. Step 2: Differentiate Hub from Nodes

   Nodes are the machines that actually run the tests, while the Hub manages these Nodes and distributes tests.

3. Final Answer:

   To manage and distribute test requests to connected Nodes -> Option C

4. Quick Check:

   Hub manages test distribution = D [OK]

Hint: Hub manages tests; Nodes run tests [OK]

Common Mistakes:

• Confusing Hub with Node
• Thinking Hub runs tests locally
• Assuming Hub stores test data

2. Which of the following is the correct way to start a Selenium Grid Hub using the command line?

easy

A. java -jar selenium-server.jar hub

B. java -jar selenium-server.jar node

C. java -jar selenium-server.jar start

D. java -jar selenium-server.jar run

Solution

1. Step 1: Identify the command to start the Hub

   The command to start the Hub is 'java -jar selenium-server.jar hub'.

2. Step 2: Differentiate Hub and Node commands

   'node' starts a Node, not the Hub. 'start' and 'run' are invalid commands here.

3. Final Answer:

   java -jar selenium-server.jar hub -> Option A

4. Quick Check:

   Hub starts with 'hub' argument = A [OK]

Hint: Use 'hub' to start Hub, 'node' for Nodes [OK]

Common Mistakes:

• Using 'node' instead of 'hub' to start Hub
• Using invalid commands like 'start' or 'run'
• Omitting 'java -jar' part

3. Given the following Java code snippet for Selenium Grid, what will be the output if the Hub URL is incorrect?

RemoteWebDriver driver = new RemoteWebDriver(new URL("http://localhost:4444/wrongpath"), new ChromeOptions());
driver.get("https://example.com");

medium

A. SessionNotCreatedException at runtime

B. org.openqa.selenium.WebDriverException: Unable to connect to Grid Hub

C. MalformedURLException at compile time

D. No output, test runs successfully

Solution

1. Step 1: Analyze the URL used for RemoteWebDriver

   The URL "http://localhost:4444/wrongpath" is incorrect for the Grid Hub endpoint.

2. Step 2: Understand the error caused by wrong Hub URL

   RemoteWebDriver will throw a WebDriverException because it cannot connect to the Hub at the wrong URL.

3. Final Answer:

   org.openqa.selenium.WebDriverException: Unable to connect to Grid Hub -> Option B

4. Quick Check:

   Wrong Hub URL causes connection error = B [OK]

Hint: Wrong Hub URL causes connection failure error [OK]

Common Mistakes:

• Expecting compile-time error for URL string
• Confusing SessionNotCreatedException with connection error
• Assuming test runs despite wrong URL

4. Identify the error in the following Selenium Grid Node registration command:

java -jar selenium-server.jar node --hub http://localhost:4444/hub --port 5555 --role node

medium

A. The port number 5555 is invalid for Nodes

B. The '--hub' URL should not include '/hub' at the end

C. The command is correct and will register the Node successfully

D. The '--role node' option is unnecessary and causes error

Solution

1. Step 1: Review the Node registration command syntax

   The '--role node' option is not required and may cause errors because 'node' is implied by the command.

2. Step 2: Check other parts of the command

   The '--hub' URL including '/hub' is correct, and port 5555 is valid for Nodes.

3. Final Answer:

   The '--role node' option is unnecessary and causes error -> Option D

4. Quick Check:

   '--role node' is redundant and wrong = C [OK]

Hint: Avoid '--role node' when starting Nodes [OK]

Common Mistakes:

• Removing '/hub' from Hub URL incorrectly
• Thinking port 5555 is invalid
• Assuming command is correct without checking options

5. You want to run tests on Chrome and Firefox browsers simultaneously using Selenium Grid. Which setup steps are necessary to achieve this?

hard

A. Start one Hub, register two Nodes each configured for Chrome and Firefox respectively, then use RemoteWebDriver with desired capabilities

B. Start two Hubs, each with one Node for Chrome and Firefox, then run tests separately

C. Start one Node with both Chrome and Firefox drivers, no Hub needed, run tests locally

D. Start one Hub and one Node with only Chrome driver, then switch drivers in test code

Solution

1. Step 1: Understand Grid architecture for multiple browsers

   One Hub manages multiple Nodes. Each Node can be configured to support different browsers like Chrome and Firefox.

2. Step 2: Setup Nodes and test code

   Register two Nodes with the Hub, one for Chrome and one for Firefox. Use RemoteWebDriver with desired capabilities to select browser at runtime.

3. Final Answer:

   Start one Hub, register two Nodes each configured for Chrome and Firefox respectively, then use RemoteWebDriver with desired capabilities -> Option A

4. Quick Check:

   One Hub + multiple Nodes + desired capabilities = A [OK]

Hint: One Hub, multiple Nodes for browsers, use capabilities [OK]

Common Mistakes:

• Starting multiple Hubs unnecessarily
• Skipping Hub and running Node alone
• Using one Node with single browser only