Headless Browser Testing in Selenium

Let’s explore Headless Browser in Selenium and see how it works.

Introduction

 A Headless Browser is a browser simulating program that does not have a Graphical User Interface (GUI)

Headless Browser operates like any other browser but does not display any UI.

What is Headless Testing?

The process of executing the web applications UI tests without opening a browser’s user interface is called Headless Browser Testing. Test Automation scripts run in background when we run it in headless mode. We cannot see the execution but it will simulate all the actions in the backend. Almost all the modern browsers have the capability to run in headless mode.

When to use Headless Browser Testing?

•  We can use Headless Testing once the Cross-Browser testing is completed and want to run regression test cases in subsequent releases and with continuous integration,

• Headless Browsers are used when the machine does not have a GUI.

•  It is recommended to use Headless Browser when tests are executed in parallel as User Interface based browsers consume a lot of Memory.

• Headless Browsers can be used when there is no need to view anything, and our purpose is to ensure that all tests are executed successfully line by line.

  
  

Benefits of Headless Browser Testing

• One of the significant benefits of using Headless Browsers is performance. Since Headless Browsers don't have a GUI, they are faster than real browsers.

• Headless mode is well-suited for integrating with CI/CD pipelines where resources are limited.

• Headless mode makes it easy for Web Scrapping in the backend.

• When compared to real browsers Headless Browsers are faster so these are chosen for faster execution over real browsers.

• Headless Browser Testing is high-speed compared to real browsers as it consumes fewer resources from the system they run on.

Limitations of Headless Browser Testing

• Debugging the browser in headless mode is quite complex.

• Recording of test execution is not possible as there is no GUI.

• It is hard to diagnose where the test execution is failing.

  
  

How to automate Headless Browser in Selenium?

Usually, we initialize the WebDriver then use the get method to get the URL it will automatically open the browser but our intention here is not to open the browser in a UI and everything needs to happen in the backend which is possible only with the headless mode. Let’s see how to do Headless Testing in three different browsers using three different classes.

 Headless Testing in Selenium for Chrome using Chrome Options

What is Chrome Options Class?

You might have this question. Let me answer to your question. This Chrome Options class is a class which is used to manage all the options specific to the chrome Browser

Selenium provides a special class called Chrome Options class to modify the default characteristics of the browser, add Arguments () method of Chrome Options helps to run the tests on the headless mode by passing headless or –headless as an argument, as seen in the commands below.

OR

Later pass the options as an argument when instantiating the Chrome Driver object.

Let’s look at the following code on how to automate test in selenium by using Headless mode in Chrome.

First  create a Maven project, add the Selenium Java and TestNG dependencies in the pom.xml file and save it to download the dependencies.

Second  create a package under source test java and create a class as Chrome Headless.

Explanation of the code

• Create a method.

• Launch the chrome browser by using WebDriver Manager class

• Create a special class named Chrome Options with an object.

•  Include a method add Arguments () and passing the argument as (“headless”) OR (“—headless”)

• Instantiate the driver and passing the Chrome option object to the driver.

• Call the driver to open the URL

• Use the print statement to capture the output in the console as the UI is not visible.

• Add assertions to the test.

• Close the driver.

Run the test

Headless Testing in Selenium for Firefox using Firefox Options

Firefox Headless browser works just like Chrome Headless Browser. Selenium provides Firefox Options class to modify the default characteristics of the browser. add Arguments () method of Firefox Options helps to run the tests on headless mode by passing –headless as an argument.

The following code shows how Headless Testing can be achieved in Firefox Browser.

Create a class as Firefox Headless

Run the test

Headless Testing in Selenium for Edge using Edge Options

Just like Chrome and Firefox, Microsoft Edge Browser can also be run in Headless Mode. Edge Options class of Selenium is used to manage options specific to the Edge browser. Add Arguments () method of Edge Options helps to run the tests in the headless mode by passing headless or –headless as an argument.

The following code shows how Headless testing can be achieved in Edge Browser. With Edge Options class.

Create a class as Edge Headless

Run the test

Conclusion:

To conclude, besides its limitations, Headless mode in selenium is used to run the test scripts in order to increase the performance and reduce the execution time.

Hope this blog helps you in understanding the concept of Headless testing in Selenium.

Happy Learning!