Selenium Architecture – Working, Diagram, Advantages, & More

In 2004, Jason Huggins developed Selenium after realizing the shortcomings of manual testing. Initially developed as an internal testing tool, it is now used worldwide by programmers and developers. But do you know how this tool works? This blog will discuss the Selenium architecture and how it works to run a successful web application test. We will also learn about its components, features, advantages, limitations, and more.

What is Selenium?

Selenium is an open-source tool that automates web application testing on various browsers and operating systems. If you wish to get a more comprehensive look at Selenium, you can refer to this software testing course. It covers topics like Java basics, Selenium, Selenium WebDriver commands, etc.

What is Selenium Architecture? 

The WebDriver architecture in Selenium is about the internal workings of the Selenium tool. It consists of four components that enable it to run web application tests.These components are as follows: 

1. Selenium WebDriver Client Libraries

Selenium Client libraries, or language bindings, are programming libraries that contain commands in the form of external jar files. These files are compatible with the W3C Selenium Protocol. Client Libraries have two components, WebDriver Protocol Clients and WebDriver-based tools. These language bindings help support multiple languages in Selenium. 

2. JSON Wire Protocol

JavaScript Object Notation or JSON is an important component in Selenium architecture. It is an open standard for exchanging data between a client and a server. It converts the requests sent by clients to HTTP requests for the understanding of the server and converts them back when sending them to the client. 

 JSON acts as the industry standard for a lot of other REST (Representational State Transfer) web services because of its quality of reading and writing data with ease. 

3. Browser Drivers

Browser Drivers help Selenium commands run in browsers, acting as a link between the Selenium Client Libraries and these browsers. Every browser has a driver specific to it. They are used to establish a secure connection with the browser without revealing the internal logic of the browser’s functionality.

4. Browsers

Selenium supports various browsers, such as Chrome, Internet Explorer, Safari, Firefox, etc. These are used to run Selenium test scripts for automated web application tests.

Other than the above-mentioned components, Selenium WebDriver also needs the Selenium API to work on tests. 

Selenium and Its Components

You can use multiple programming languages in a single framework to develop a Selenium test script. It has the following four suite components:

• Selenium IDE: This Integrated Development Environment is a Firefox plugin. It was created for faster development of automation scripts. 
• Selenium RC: With this, the users can write application tests in various programming languages. It relies on JavaScript for automation. However, it does not support recording or playback features.
• Selenium WebDriver: It directly communicates with the browser by accepting and sending commands. 
• Selenium Grid: It helps in running parallel tests on different machines against different browsers and operating systems.

Features of Selenium

Selenium is a preferred web application testing tool because of its various features. The following are some of them:

• Dynamic Web Elements: Selenium can handle dynamic web elements easily with methods, such as absolute XPath(), StartsWith(), and contains().
• Automation of Test Scripts: Selenium allows the user to automate the testing scripts, ensuring faster and more reliable testing.
• Multi-Browser Support: It supports multiple browsers, including popular ones like Microsoft Edge, Google Chrome, Safari, Mozilla Firefox, Opera, etc. 
• Open Source Tool: Selenium is an open-source and portable tool you can easily download from its official website. It also ensures a wider community support of Selenium users.
• Parallel Test Execution: It allows the users to run parallel tests for increased efficiency and saves time. 
• Multi-Language Compatibility: It allows writing test scripts in several programming languages, such as Python, Perl, JavaScript, Ruby, PHP, Java, and more.

How Does Selenium WebDriver Work?

To begin your testing process, you will have to write a test script in your user interface, for example, ‘Eclipse IDE’. When you run this code, it will open the browser and take you to the mentioned URL. Take this code as an example. It, upon execution, will open the Chrome browser and take you to the Internshala trainings. 

WebDriver driver = new ChromeDriver();
driver.get(“https://trainings.internshala.com/”);

However, this is a very simple understanding of the working of the WebDriver architecture in Selenium. The internal process is much more intricate and looks somewhat like this:

• Once you run your test script, the Selenium client library communicates with the Selenium API, 
• API is responsible for sending programming language commands to the browser driver. 
• These commands are sent through the JSON wired protocol, which in turn converts them into HTTPS requests. 
• The browser driver receives HTTPS requests from an HTTP server. Here, it filters the command that needs to be worked on and sends it to the browser, where it is finally executed.
•  Drivers and APIs further convert the response received from the HTTP server after the execution of the commands and convert them back to JSON format. 
• After this, we get the final results, which are recorded.  

Selenium WebDriver Architecture Diagram

For a better understanding of the above-mentioned process of testing in Selenium WebDriver, here’s a diagram.

Advantages of Selenium WebDriver

The following are the advantages of Selenium architecture.

• It is an open-source tool. 
• It is capable of running tests across browsers. 
• It is compatible with many operating software and supports various programming languages. You can download the language bindings suitable for your tests easily and work on them. It even supports iPhone and Android operating systems.
• It allows for parallel testing, which saves a lot of time.
• For code compilation, it supports integration with various frameworks, such as Maven and ANT.
• For improved automation testing and reporting experience, it supports integration with third-party tools, such as TestNG and Junit.
• Unlike some of the other Selenium components, starting up a server is not required in WebDriver for testing.
• Through Selenium WebDriver, one can implement user gestures, such as mouse cursor and keyboard actions. Also, advanced browser interactions are allowed, such as clicking on the front and back buttons of a browser.
• Jenkins integrated with Selenium WebDriver helps in CI/CD purposes. 
• Troubleshooting is easy due to strong community support. 

Limitations of Selenium WebDriver

Here are some of its limitations:

• It does not support mobile or desktop applications and tests only web applications.
• Automatic test reports are generated only with the help of third-party tools, such as TestNG.
• It does not automate Captcha, barcodes, or fingerprints.

Conclusion

WebDriver Client Libraries, JSON wire protocol, browser drivers, and browsers are all integral components of the Selenium WebDriver architecture. They work together to ensure WebDriver runs the tests efficiently without errors, which is important for an enhanced software testing experience. 

Did you find this blog informative? Share your thoughts with us in the comments section below. To gain in-depth knowledge of the Selenium Suite, refer to this blog exploring different types of Selenium components.