How to run parallel tests with Selenium Standalone?

Question

I am developing a Java-based test automation project and using Selenium Standalone to run my tests. Currently, I can run tests on a single browser instance, but I want to execute parallel tests.

I tried using Selenium Grid, but I couldn't configure it properly. As an alternative, I attempted to run two separate Selenium Standalone instances on different ports (e.g., 4444 and 4445). However, I am not sure how to distribute tests between these instances in my code.

I know that Selenium Grid handles this automatically, but how can I manage parallel test execution using Selenium Standalone?

Any guidance on how to structure my code for this would be greatly appreciated!

I tried running two Selenium Standalone instances on ports 4444 and 4445. I expected my tests to distribute between them automatically, but instead, all tests ran on a single instance. I need a way to manage parallel execution across multiple standalone instances.

Answer 1

Start the Selenium Grid Hub

First, launch the Hub, which will manage test distribution:

java -jar selenium-server-4.x.jar hub 

Connect Nodes to the Hub

Now, start two nodes on different ports (you can add more if needed):

java -jar selenium-server-4.x.jar node --port 5555 --hub http://localhost:4444 java -jar selenium-server-4.x.jar node --port 5556 --hub http://localhost:4444 

These nodes will execute the tests assigned by the Hub.

Connect to Selenium Grid in a Test Class

In your test code, configure WebDriver to connect to the Grid Hub. Here’s an example using JUnit 5:

import org.junit.jupiter.api.AfterEach; import org.junit.jupiter.api.BeforeEach; import org.junit.jupiter.api.Test; import org.openqa.selenium.WebDriver; import org.openqa.selenium.chrome.ChromeOptions; import org.openqa.selenium.remote.RemoteWebDriver; import java.net.MalformedURLException; import java.net.URL; import static org.junit.jupiter.api.Assertions.assertTrue; public class SeleniumGridTest { private WebDriver driver; @BeforeEach void setUp() throws MalformedURLException { // Specify Selenium Grid Hub URL URL hubUrl = new URL("http://localhost:4444/wd/hub"); // Browser options (you can also use FirefoxOptions, etc.) ChromeOptions options = new ChromeOptions(); // Create a Remote WebDriver driver = new RemoteWebDriver(hubUrl, options); } @Test void testGoogleHomePage() { driver.get("https://www.google.com"); String title = driver.getTitle(); System.out.println("Page Title: " + title); assertTrue(title.contains("Google")); } @AfterEach void tearDown() { if (driver != null) { driver.quit(); } } } 

Answer 2

You do not need Selenium Grid to run tests in parallel. Modern computers have multiple cores or processors - you can utilize this to run tests vertically instead of horizontally.

As your project is based on Java - you can run tests in parallel using the TestNG test runner. Below is an example of how it can be done or configured.

Answer 3

Running Tests in Parallel using Selenium Grid To execute tests on several browsers or machines, you can run Selenium Grid rather than a standalone server.

1. Run Selenium Grid in Standalone Mode: java -jar selenium-server-4.x.x.jar standalone

2. WebDriver driver = new RemoteWebDriver(new URL("http://localhost:4444/wd/hub"), new ChromeOptions());

3. Perform the tests as given in the JUnit or TestNG sections.