What is Selenium? Introduction to Selenium Automation Testing

What is Selenium?

Selenium is a set of tools and libraries that are used to automate web applications across different platforms using different programming languages. In simple words, this tool provides functionalities that can interact with the browser and automate browser actions like click, select, input, navigate, etc., with the help of scripts. Testing done with the help of this tool is referred to as automated testing. It is free and open-source. It is the most widely used open-source solution for Selenium automation testing of web applications.

Selenium is usually not just a single tool but a suite of tools. It has four components.

Selenium IDE( Integrated Development Environment)
Selenium RC(Remote Control)
Selenium WebDriver
Selenium Grid

History of Selenium?

This tool was developed by Jason Huggins in 2004 while he worked for ThoughtWorks in Chicago. Initially named “JavaScriptTestRunner,” it was later renamed “Selenium Core” and released to the market as an open-source tool. Day by day, this open-source tool started gaining demand in the market, and people began using it to automate repeated tasks in their web applications.

The Same Origin Policy” Issue

Previously third-party JavaScript programs were able to access or do necessary modifications to the web applications. When the web applications become more advanced and their complexity got increased, the same has increased concern for their security measures. The Web Applications had stared restricting the external JavaScript program from accessing the internal functionalities of their applications by considering them as a security violation, which is called as “Same Origin Policy”.

As days passed, people started using “Core” for automating their web applications for repeated tasks. Later on, different web applications began following the “Same Origin Policy” as a security measure, which became an issue for “Core” and restricted it from accessing the web applications. In simple terms, the JavaScript program of an X domain cannot able to access the pages hosted at a different domain say Y domain.

To overcome this, testers started installing both Core and the web application code under test in the same domain and then automated the required tests.

Selenium RC

As the testing team faced difficulties in installing Core and the web application code on their local machines due to the “Same Origin Policy” issue while automating their tests, another individual named “Paul Hammant” came up with the idea of creating a Proxy Server. This server tricked the browser into believing that Core and the web application code belonged to the same domain, and it was named “Selenium RC.”

Selenium Grid

When there are large numbers of tests to be executed in the project, the Grid comes into the picture. A guy named “Patrick Lightbody” came up with a solution known as “Selenium Grid” to overcome the test execution time. Using Grid, testers were able to distribute the tests across multiple machines and execute them on different machines to minimize the test execution time.

Selenium IDE

A guy named “Shinya Kasatani” developed a Firefox extension named “Selenium IDE” to increase the speed of automation test creation. IDE is a record-and-playback tool used to record automation tests and execute the recorded tests.

Selenium WebDriver

To overcome the “Same Origin Policy”, the guy “Simon Stewart” has come up with the first cross-platform testing framework that can control the browser from the OS level and he named the cross-platform testing framework as “Selenium WebDriver”.

Selenium 2

In 2008, Selenium Team has decided to merge Selenium RC and Selenium WebDriver to form a more powerful tool known as Selenium. Since “WebDriver” being the core and “Selenium RC” used to run in maintenance mode.

Selenium 3

In this version, the dependency for RC was completely removed, and the latest version was known as Selenium 3.

Selenium 4

Simon Stewart, the founder of the tool, had officially released version 4 with some of the major updates. The 4.0 version of the world’s beloved framework for web testing automation was released in December 2018. The new version is completely W3C standardized. Nowadays, it has become the industry standard for developing automated tests and is recognized as the first go-to solution for every web application that has grown out of an approach where manual testing could have solved most of the problems.

In present days, most businesses heavily rely on this tool, not only those with automation QA engineers on their team but also those who have integrated codeless automation testing. Codeless testing based on this tool has become a real lifesaver for everyone in the current market who realizes the importance of automation but lacks implementation knowledge. Such tools not only help make deployment easy but also make it possible to run regression tests and perform load testing without any knowledge of the framework at all.

Selenium IDE Introduction

SeleniumIDE (Integrated Development Environment) is the simplest tool in the components suite. It is the tool you use to develop test cases. It is an easy-to-use Firefox add-on that creates tests quickly through its record and playback functionality.

Advantages of IDE

Record and Playback tool
Complete / Individual scripts can be executed
Select the option to capture locators of elements

Disadvantages of IDE

Available only on Firefox browser and chrome browser as plugin
If, else statements cannot be applied
For loop, while loop cannot be applied
Values cannot be passed from outside
Cannot implement Frameworks
No parameterization and synchronization

Selenium RC Introduction

Selenium RC (Remote Control) was one of the first tools in the Selenium suite to allow automated web application testing across different browsers. It uses a client-server architecture, where the RC Server acts as a proxy to interact with web browsers. With Selenium RC, testers can write test scripts in multiple programming languages, making it more flexible than Selenium IDE.

Advantages of Selenium RC

Multi-language Support: Allows writing test scripts in multiple programming languages like Java, Python, Ruby, etc.
Cross-Browser Testing: Supports multiple browsers beyond just Firefox or Chrome.
Server Interaction: Facilitates interaction with the server, enabling dynamic testing scenarios.

Disadvantages of Selenium RC

Complex Setup: Requires installation and setup of the RC server, adding complexity compared to newer tools.
Slower Execution: Test execution is slower because of the client-server communication overhead.
Deprecated Tool: Selenium RC is outdated and has been replaced by Selenium WebDriver.
Limited Debugging: Debugging and troubleshooting test scripts can be challenging.

Selenium WebDriver Introduction

Selenium WebDriver is a set of tools, which is used to automate on different browsers. It is easy to explore and understand compare with Selenium RC. And it will help to make your test easier to read and maintain.
Selenium WebDriver supports the following languages

Java
Python
C#
Ruby
Perl
PHP

Advantages of Selenium WebDriver

Supports multiple browsers like Chrome, Firefox, Edge, and Safari.
Compatible with multiple programming languages, including Java, Python, C#, and Ruby.
Allows integration with other testing tools and frameworks like TestNG and JUnit.

Disadvantages of Selenium WebDriver

Requires programming knowledge to implement test scripts.
Lacks built-in reporting capabilities; requires integration with external tools.
Cannot handle captcha or visual verifications effectively.
Limited support for testing desktop applications.
Debugging can be complex, especially in large test suites.
Requires additional effort for setting up environments and maintaining scripts.

Selenium Grid Introduction

Selenium Grid is a tool that extends Selenium RC by running tests on different instances in parallel. It reduces the time, cost for testing in various browsers under multiple operating systems.

Features:

Saves time
Can run tests in multiple browsers and environments simultaneously
Utilize the Hub and Node concept, where the hub will be the central machine that will redirect the commands to the respective node and the node will be the actual machine where the test will get executed.

Advantages of Selenium Grid

Enables parallel test execution across multiple machines and browsers.
Reduces total execution time for large test suites.
Supports distributed testing environments, allowing tests to run on remote systems.

Disadvantages of Selenium Grid

Complex setup and configuration, especially for large grids.
Requires robust infrastructure to handle distributed testing effectively.
Debugging issues across multiple nodes can be challenging.
Dependency on a network connection; poor connectivity impacts execution.
Limited documentation for advanced configurations.

Platforms supported by Selenium

Selenium works with different browsers, Operating systems, programming languages and Frameworks

Browsers

Chrome
Firefox
Internet Explorer
Opera
Safari

Operating Systems

Windows
Macintosh
Linux

Programming Languages

Java
Python
C#
Ruby
Perl
PHP

Frameworks

Java – TestNG or JUnit
C# – NUnit
Python – unit test

Advantages of Selenium

It is an Open Source Tool
It supports multiple browsers
It supports multiple Operating Systems
It supports multiple languages
It supports distributed test execution
It can integrate with other tools like Maven, Ant, TestNG, NUnit, JUnit, etc.
It can handle JavaScript Errors in the application
It can simulate the actions performed by human
The browser can be minimized while executing the code and can do our other works
It supports many IDEs, Eclipse for Java language and Visual Studio for C#

Disadvantages of Selenium

It automates only web-based applications
The tester should have the programming knowledge to automate the applications
Selenium does not generate any in-built report
Image comparison is not possible
Captcha and Bar Code readers cannot be automated
Recovery scenario is not available by in-built

Difference between Selenium and QTP

Selenium is an open-source tool, whereas QTP is a paid tool.
Selenium is used to test web-based applications only while QTP test a wide variety of applications like a web-based, desktop.
Selenium supports scripting in different languages like Java, .Net, Python, Ruby, Perl, etc. while in QTP supports only VBScript language.
Web Automation testing with selenium requires no cost to buy whereas QTP requires paid license.

Advantages of Selenium over UFT

Selenium	UFT
Selenium is an Open-Source Tool	UFT is a Paid Tool
Can run tests across multiple browsers(Chrome, Firefox, Opera, IE, Safari)	Can run tests only in Firefox, Chrome and Internet Explorer
Supports multiple Operating Systems	Can only be used in Windows Operating System
Can run tests in parallel	Can only execute tests in parallel by using Quality Center
Can run tests even while the browser is minimized	Needs to have the AUT(Application Under Test) to be visible on desktop

Conclusion

Each automation tool comes with its unique set of strengths and limitations, and choosing the right tool often depends on the specific requirements of the testing process and the expertise of the user. Understanding what to test, how to execute the operations, and the tool’s compatibility with the project’s environment is crucial in making an informed decision.

While QTP (Quick Test Professional) is widely recognized in the industry, it caters to specific needs and scenarios.Being open-source, some tools excel in providing flexibility, cost-effectiveness, and support for a wide range of browsers and platforms, making them ideal for web application testing.

Ultimately, the choice between tools like QTP depends on project-specific needs, such as the type of application being tested, the budget, team expertise, and long-term maintenance considerations. Evaluating these tools against the desired outcomes can help testers strike a balance between functionality and efficiency, ensuring a smooth and effective testing process.

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