Types of Selenium Components – A Comprehensive Overview

A Quality Analyst Engineer’s most powerful weapon is automation testing. That era no longer exists, when testing was done after software or web application development. Automation testing optimizes continuous testing activities and has replaced human testers. One of the most popular tools for automation testing is Selenium. It came into being in 2004, and since then, it has taken over the stage.
This blog will take you through a brief introduction to selenium components that are essential for the automation testing of web applications.

What is Selenium?

Selenium is a free and open-source automation testing suite. It focuses on the automated testing of only web applications across different browsers and platforms. 

For web applications to operate without a hitch, testing is necessary. It helps detect issues with the website. Testing all the essential components of the website is done to ensure that the end-users do not face any problems while using it. The widely used Selenium testing tool makes web application testing easy.

Selenium testing cannot be used to test desktop applications or mobile applications. There are other tools available for testing desktop and mobile applications, such as  IBM’s RFI, HP’s QPI, Appium, etc.

Why Selenium Testing?

The Selenium testing suite has an advantage over other testing tools for web applications. Some of the reasons that give selenium an edge over others are:

• Since this is a free, open-source tool, there are no license fees.
• Programming scripts for tests are frequently created in one of the following languages: Java, Python, C#, PHP, Ruby, Perl, or .Net. You can choose to learn any of these programming languages and may start with a Python course available online.
• Any of these operating systems—Windows, Mac, or Linux—can be used to run the tests.
• Any of the following web browsers, including Google Chrome, Safari, Opera, Mozilla Firefox, and Internet Explorer, can be used to run the tests.

There are various selenium testing components available. Let’s take a look at them.

Selenium Suite Components

The Selenium software has four components to enable different testing needs of the code and applications. The selenium suite components are:

• Selenium IDE
• Selenium RC
• Selenium WebDriver
• Selenium Grid

1. Selenium IDE

IDE stands for Integrated Development Environment. Initially, it was supported by Firefox, now both browsers – Firefox and Chrome are used to run the IDE testing tool. This means you cannot run tests on browsers other than these two.

Features of the Selenium IDE are:

• It has a simple framework, easy to use and install. For example, its installation in Firefox is easy. Simply launch the browser and go to the “add-on page” of Firefox to add the Selenium IDE plug-in. 
• Test cases are created with the help of browser interactions, which rule out the need for a programming language to write test scripts. Thus, enabling the testers to record and playback test cases for automated testing of web applications.
• Selenese, a scripting language, is used to create test cases. 
• It supports various programming languages such as C#, Java, Ruby, or Python and allows users to export the recorded tests into these languages.
• It also allows users to edit the tests, debug them, and set breakpoints to pause the test execution at any point.

In Selenium IDE, the execution of test cases is generally slow compared to other components.

2. Selenium RC

RC stands for Remote Control. Selenium RC (Remote Control) is a server, written in Java, that accepts commands for HTTP-based browsers. 

Features of Selenium RC are:

• It supports other programming languages such as Ruby, PHP, Python, Perl, C#, Java, and Javascript for automation testing.
• It runs on almost every web browser and operating system.
• With the help of the other component, Selenium Grid, it supports the parallel execution of various test cases.
• The components of Selenium RC include the following:
  • Selenium Server is a bridge between the code and the browser. It is responsible for interpreting and executing Selenium commands sent by the test scripts. It launches and kills browsers and serves as an HTTP proxy server to intercept and verify various web requests.
  • Client libraries exist to provide a bridge between the Selenium server and other programming languages.

Executing a test program on Selenium RC requires starting the Selenium server manually. To overcome this manual start, the Selenium WebDriver was launched.

3. Selenium WebDriver

This component of the Selenium suite is an extension to Selenium RC. It was built to overcome the limitations of Selenium RC and allows for direct communication with the browser without manually starting the server for testing processes.

Features of Selenium WebDriver are:

• It is a set of APIs (Automated Programming Interfaces) that enhance web testing applications.
• Every browser has a separate web driver, and they accept Selenium commands to run the test scripts.
• It supports multiple programming languages and is cross-browser-compatible.
• It does not support the recording and playback of test script feature like Selenium IDE. 
• It supports web pages with dynamic elements in such a manner that any element that will appear on the page can change without requiring a reload of the page.
•  It offers high-speed execution and can be integrated with testing frameworks such as JUnit and TestNG.
• It has four basic components:
  • Selenium Language Bindings/Client Libraries:The language bindings, or client libraries, support multiple programming languages such as Java, Ruby, Python, C#, and JavaScript. These libraries are jar files that contain Selenium WebDriver classes and methods needed for automation test scripts. Selenium client libraries are not a testing framework, but rather an application programming interface (API) for running Selenium commands from within the program.
  • JSON Wire Protocol: JSON means JavaScript Object Notation that supports data interchange formats in languages like Java, C#, Python, Ruby, etc. It helps to exchange data between the client and server on the web.
  • Browser Drivers: Secure communication between Selenium and each browser is established using a specific driver. Using the wire protocol, WebDriver implements the appropriate operations for each browser based on the requests received from language bindings.
  • Real and Headless Browsers: The headless browser does not have a user interface, whereas a real browser does. For example, Chrome is a real browser, and HTMLUnit browser is a headless browser. Selenium WebDriver automation testing on both browsers. 

4. Selenium Grid

The Selenium Grid is a tool used with Selenium RC to execute tests parallelly on different machines and browsers.

Features of Selenium Grid are:

• It reduces the execution time of the testing suite because it runs parallel execution of tests across different machines and browsers. 
• It consists of two major components:
  • Hub: A hub is a central machine that triggers test cases within a Selenium grid. Upon receiving test requests, it distributes them to nodes. A Selenium grid only has one hub.
  • Node: Nodes execute test cases loaded on a hub, launching on multiple machines, platforms, and browsers.

Conclusion

Selenium testing is synonymous with automation testing. The automated testing of web applications has been accelerated with the help of Selenium components. Become an efficient quality tester by deepening your knowledge of these components with this guide.