In the modern world, hundreds of mobile and web applications are being deployed. The QA team has to always ensure that the web apps are functional outside the development zone. Earlier, these tasks were executed manually. Enter Selenium. It changed the way testing was performed. Now, automation has become widely famous in every industry since it saves time and cost and provides plenty of advantages to businesses. Selenium is one of the best-automated testing tools useful for various organizations in the world of web application development. It is indeed a useful and powerful tool that offers plenty of good things. Developers, who want to be confident about the application features without spending a lot of time testing the front end of the web applications, can use Selenium for their purpose. In addition, Selenium saves your time by automation your repetitive tasks. In this article, I’ll discuss Selenium, Selenium Webdriver, its components, supported languages, some of the key features, and real-world use cases. Let’s begin!
What is Selenium?
Selenium is an automation tool for web applications. It is an open-source portable framework that various organizations and developers use to automate their critical tasks. When it comes to testing regression and functional test cases, Selenium is highly flexible. Selenium supports automation across various platforms, programming languages, and browsers. Its test scripts are written in various programming languages like Python, C#, Java, and more. These scripts run across different browsers like Safari, Firefox, Chrome, Opera, etc., supporting platforms like macOS, Linux, Windows, Solaris, etc. Selenium supports cross-browsing functionality and helps in creating browser-based and robust regression automation suites. It was first developed by Jason Huggins in the year 2004, he was working as an engineer on a web application that needs regular testing. So, he created a program through JavaScript and realized the shortcomings of manual testing. At first, he named the program ‘JavaScriptTestRunner’. After realizing the potential of the program, Jason Huggins made it an open-source platform which he renamed Selenium Core.
How is Selenium Useful?
Developers and organizations use Selenium when it comes to testing web applications because Selenium empowers developers to perform automated testing. In fact, a piece of software comes with a complex architecture and is also prone to regressions. From adding new features to fixing defects, every function related to this can cause existing features to stop working. This is the main reason automated testing is the most useful step in the programming world. Since testing the application manually after every tiny change to the features is impractical, Selenium provides you with a better solution for reducing such hectic tasks. It allows organizations and developers to simulate the testing of each interaction with the web applications across various browsers.
Selenium Tool Suite
Selenium comprises a large suite of tools or components. Let’s discuss each.
#1. Selenium IDE
You can automate your web applications’ testing by using a record and playback automation component called Selenium IDE. It comes in the form of a Firefox and Chrome browser extension. People with low and limited programming experience can use this tool as it works on the recording and playback principles.
#2. Selenium RC
Selenium RC is used to insert JavaScript code in any browser for automation. It also requires an additional server to run those automation scripts. But it has some limitations, such as it is slow, it doesn’t have a headless browser like HtmlUnitDriver and it is needed to start the server before executing any test scripts.
#3. Selenium WebDriver
Selenium Webdriver is one of the most important components of Selenium. It offers various drivers for multiple browsers and supports different programming languages. In addition, it is object-oriented and supports almost all browsers, such as Firefox, Chrome, IE, Safari, and more. The scripting can be done by using popular languages, including Python, Ruby, Java, and more.
#4. Selenium Grid
Selenium grid is again an essential part of Selenium. It helps distribute the running of automated tests in parallel across different remote machines. The Grid consists of a hub and various nodes. These nodes run the instances of the Selenium suite on which you can execute test cases. The central hub acts as a server and the nodes are connected to it in order to control the whole test execution.
Selenium WebDriver in Detail
In general, a WebDriver is a set of Application Programming Interfaces (APIs) and is an object-oriented tool that has a lot of capabilities. It offers communication facilities between browsers and languages. WebDriver is used to execute various tests in multiple popular browsers. Moreover, it contains different types of abstract methods like findElement(), By(), get(), etc. In 2009, Selenium RC is merged with WebDriver to create a new Selenium tool called Selenium WebDriver or Selenium 2.0. Now, Selenium Webdriver is a popular tool of Selenium. It offers open-source and free libraries to developers in order to automate the testing of web applications. In Selenium WebDriver, test scripts are developed using various supported programming languages. It can be run in the most modern web browsers. Moreover, it supports different languages, such as Perl, Python, Ruby, Java, PHP, and C#. But currently, Selenium WebDriver is most popular with C# and Java. It performs much faster than Selenium RC as it makes a direct call to the browsers. Furthermore, WebDriver consists of a built-in implementation of Firefox Driver or Gecko Driver. To perform testing in other browsers, you need to plug in browser-specific drivers in order to communicate and run the automation testing. The most used WebDrivers are:
Google Chrome Driver Opera Driver Internet Explorer Driver HTML Unit Driver – headless driver Safari Driver
Selenium WebDriver is well-known due to its stability and diversity for web automation. More than 80% of companies are using Selenium WebDriver as it is the easiest way for UI automation.
Components of Selenium WebDriver
Selenium WebDriver consists of four basic components:
Selenium Language Bindings JSON Wire Protocol Browser Drivers Real Browsers
Let’s discuss the core components of Selenium WebDriver in detail.
#1. Selenium Language Binding/ Core Libraries/ Selenium Client
Automation scripts interact with the Selenium server through the Webdriver. It is written in different programming languages, such as Ruby, Python, Java, and more. Selenium developers develop language bindings that let Selenium support those programming languages. Its client libraries are simply different Jar files. These libraries have methods and classes of Selenium WebDriver, which are needed to create test scripts for automation. You can use package installers available for respective languages to install Selenium core libraries. For example, if you wish to use a browser driver in Java, you will need Java client libraries or Jar files. Selenium client libraries are not the testing framework rather they provide an API, which means a set of functions to execute Selenium commands from the program.
#2. JSON Wire Protocol over HTTP
JavaScript Object Notation (JSON) is a popular data interchange format that is based on the subset of JavaScript. JSON is used to exchange data between server and client on the web. JSON Wire Protocol supports all the data formats available in all popular languages, such as Python, Ruby, Java, etc. It is a transport mechanism that transfers data between the client and the server on the web using JSON. Furthermore, JSON uses a REST API to transfer data between the HTTP server, and every browser driver has its own HTTP server.
#3. Browser Drivers
Selenium uses specific drivers for every browser to establish secure communication without revealing any internal logic of the browser’s functionality. These drivers receive requests from the Selenium language binding and invoke the required operations on the browser. Selenium supports almost all modern browsers for automation. The browser drivers extend another class named RemoteWebDriver that implements a WebDriver Interface.
#4. Real and Headless Browser
A browser is basically a software program that people use to see or search content on the web. Selenium WebDriver supports real and headless browsers. Example: Suppose you wish to automate tests using Selenium WebDriver and execute the script in any real browser like Chrome. To do this, you will need to download the specific driver application. HTMLUnit browser (HTMLUnitDriver) is an example of a headless browser.
How Does Selenium WebDriver Work?
In a real-time scenario, when a script code is written using anyone from the supported Selenium client libraries, by clicking the right option, you can execute the program’s source code. Once you click on the run option, the browser will launch and navigate to the URL of the website. When you execute the test script using WebDriver, some steps are performed internally.
When you click the button to run, the client library run commands from the program and converts the same into the JSON format. You will find a serialized JSON format through JSON Wire Protocol over the HTTP to send to the browser driver for each command. Every browser driver then uses an HTTP server to receive the HTTP requests. JSON Wire Protocol communicates between server and client by transferring data. The HTTP server does all the necessary actions on the real browser. The browser will send the request to load the URL. After performing all the actions, the execution status is needed to be sent back to the HTTP server over HTTP. The browser driver uses the HTTP server again to receive the request and send it back to the library through JSON Wire Protocol. The client library is then passed the same back to the program. The program will then report a failure or success.
Features of Selenium WebDriver
The powerful features of Selenium WebDriver are:
Multiple browser support: Selenium WebDriver supports a wide range of web browsers and also their versions, such as Chrome, Firefox, Safari, Opera, Internet Explorer, etc. It also supports headless browsers like the HTMLUnit browser. Multiple languages support: Selenium WebDriver supports the most commonly used programming languages, such as Ruby, PHP, JavaScript, Pearl, Python, C#, etc. It will provide facilities to choose any one of the languages based on competency. You can easily start to create test scripts. Speed: Selenium WebDriver performs fast operations. It doesn’t require intermediate servers for communication with the browser. Moreover, it provides direct communication between the web browser and WebDriver Client Libraries. Simple and easy commands: The WebDriver provides easy and simple commands to implement in the test scripts. For example, if you wish to launch a browser using WebDriver, you need to use commands like new FirefoxDriver(), new ChromeFriver(), and more. Drivers, methods, and classes: WebDriver offers various solutions to handle potential changes in automation testing. Further, it helps the testers handle complex web elements, such as dropdowns, alerts, checkboxes, and more, with the use of dynamic finders. Simple API commands: WebDriver is object-oriented and compact, so encapsulation and abstraction can be used to hide unusual details. This makes Selenium WebDriver simple. Easy to install and configure: Selenium WebDriver provides an option to test the asynchronous web apps that are built using JavaScript or AJAX.
Advantages of Selenium WebDriver
Some of the advantages of Selenium WebDriver include the following:
Selenium WebDriver is a robust, freeware, open-source, and portable tool. It supports various operating systems like Windows, Linux, and Mac. It also supports third-party tools, including Apache POI, Autoit, etc. It supports parallel test execution processes, which is one of the reasons for the popularity of Selenium WebDriver. This will reduce the time in executing test cases. It supports the implementation of Listener and Dynamic finder. In Selenium WebDriver, starting up a server is not required before every execution of the scripts. You can integrate it with any third-party tools, such as JUnit and TestNG to group different test cases and generate test reports. Get continuous testing by integrating with Jenkins, Docker, and Maven.
Limitations of Selenium WebDriver
Apart from advantages, there are also some limitations in Selenium WebDriver.
Selenium WebDriver can only test web-based applications. Desktop applications and window-based applications can’t be tested using Selenium. There are no possibilities of performing testing on an image. WebDriver doesn’t generate test result files automatically. You will need to integrate it with frameworks like JUnit or TestNG or generate reports. It doesn’t support new browsers. There is no add-in assistance. Bar code readers, reCAPTCHA, and CAPTCHA can’t be automated by using WebDriver.
Use Cases of Selenium WebDriver
Selenium WebDriver has many uses in different industries for those dealing with web applications. Some of the uses are as follows:
Updating WebDrivers versions to match web browsers’ latest versions and Selenium libraries Many businesses solve synchronization issues by implementing an automation framework Storing test data into JSON Modeling the user interface of the web application under test using the Page Object Model design pattern Testing automation development using Object-Oriented Programming (OOPs) Languages Investigating failure by taking automated screenshots Removing uncertainty from the test automation Creating high-quality test results
Conclusion
Selenium WebDriver is a crucial component of the Selenium suite. It is like the brain of Selenium. The APIs in Selenium WebDriver helps in the fast functioning of the testing process. The top features of Selenium WebDriver are cross-browser testing, web page automation, modern technology support, and more. The browser drivers in the Selenium WebDriver help in interacting with the suite with the various web browsers. Hence, Selenium WebDriver is important for the entire Selenium automation testing framework.
