When discussing web automation, Selenium stands out as a widely recognized open-source test automation framework commonly utilized for web automation testing within the industry. But what is Selenium WebDriver? Selenium WebDriver is an automation framework specifically developed to automate user interactions with contemporary web browsers. It leverages a collection of open-source APIs for effective communication with browsers and adopts a browser-centric methodology for its implementation.
This article will explain what is Selenium WebDrive and demystify the comprehensive and in-depth analysis of its design and implementation.
What is Selenium?
Selenium serves as an automation testing tool and framework for web applications. It is an open-source platform tailoring the automation testing process. Selenium offers flexibility to automation testers, enabling them to script tests in various programming languages, including Python and Java.
Selenium supports various web browsers, including Safari, Firefox, Opera, and Chrome. Test scripts programmed in diverse languages can be executed seamlessly within the Selenium framework. Furthermore, it offers cross-platform browsing capabilities, enabling simultaneous testing across various platforms such as Windows, Mac OS, Linux, and Solaris. Selenium, as a leading automation testing tool, empowers developers to construct resilient and adaptable automation suites.
WebDriver employs test scripts to mimic user actions, navigate through web pages, interact with various elements (e.g., buttons, text fields, dropdown menus, forms, links), submit forms, conduct validations and assertions, and perform numerous other functions.
A substantial number of web applications are deployed daily. Consequently, testing teams must maintain a state of preparedness to verify the optimal performance of these applications beyond the confines of the development environment. To facilitate such testing procedures, a user-friendly and reliable framework becomes essential. The remarkable suite offered by Selenium has significantly contributed to the seamless deployment of numerous applications.
Components of Selenium
As is commonly understood, Selenium represents more than a mere test automation framework. In actuality, it is a comprehensive suite of testing tools, each offering distinct functionalities that are instrumental in the creation and enhancement of automation frameworks. These individual components can be utilized independently or in combination with one another to attain more robust outcomes.
The Selenium framework primarily comprises three components:
- Selenium IDE
- Selenium WebDriver
- Selenium Grid
What exactly is Selenium WebDriver?
Selenium WebDriver stands as an open-source suite of APIs tailored for web application testing purposes. It functions as a web framework, enabling seamless execution of cross-browser tests. Its primary objective revolves around automating the validation of web-based applications to ensure they meet expected performance standards. With Selenium WebDriver, users have the flexibility to opt for a programming language of their choice to craft test scripts.
Its compatibility with popular browsers, including Firefox, Chrome, Safari, and Internet Explorer, is noteworthy, facilitating streamlined cross-browser testing.
Moreover, WebDriver extends the capability to employ programming languages for test script creation, a feature distinct from Selenium IDE.
Furthermore, users can now leverage conditional operations such as if-then-else or switch-case, alongside looping constructs like do-while.
The Architecture of Selenium 3 WebDriver
Selenium 3.0 predominantly utilizes the JSON Wire protocol for facilitating communication between the user test script and the browser. This wire protocol essentially embodies a RESTful web service employing JSON over HTTP. The Selenium WebDriver architecture in Selenium 3.0 is structured around four key components.
- Selenium Client Libraries/ Language Bindings
- JSON Wire Protocol
- Browser Drivers
- Real Browsers
Selenium Client Libraries
Selenium developers have created client libraries or language bindings to allow automation scripts to interact with the Selenium framework using Selenium WebDriver. These scripts can be programmed in various languages, including Ruby, Java, C#, Python, and JavaScript. This approach enables Selenium to support multiple programming languages.
The Selenium Client Library is a distinct Java archive (Jar) file consisting of essential methods and classes from Selenium WebDriver for the test automation script development. The Selenium core libraries are easily installable through package installers provided within the respective programming languages. All supported Selenium client libraries can be accessed and downloaded from Selenium’s official download page.
A Selenium client library should be recognized as an essential tool for facilitating web testing procedures. It is crucial to note that while it is not a standalone testing framework, it offers an Application Programming Interface (API) that enables the execution of Selenium commands directly from the test script. For instance, Java bindings provide a set of functions that can be utilized to execute Selenium commands within Java-based test scripts.
JSON Wire Protocol
JSON, short for JavaScript Object Notation, is a widely recognized data interchange format derived from a subset of the JavaScript Programming Language. In Selenium WebDriver 3.0, JSON is the communication protocol between Selenium client libraries and browser drivers. JSON facilitates the handling of data structures such as arrays and objects, thus simplifying the process of data manipulation and retrieval.
The JSON requests transmitted by the client undergo conversion into HTTP requests to facilitate server comprehension and are subsequently reconverted back into JSON format before being transmitted back to the client. This data transfer process is commonly referred to as serialization. Through this approach, the internal workings of the browser remain confidential, enabling the server to interact with Selenium client libraries even in cases where unfamiliarity with specific programming languages exists.
Browser Drivers
Browser drivers serve as an intermediary connecting the Selenium client libraries with actual web browsers, facilitating the execution of Selenium commands on browsers. A crucial component of Selenium WebDriver, they are responsible for carrying out user actions such as mouse clicks, page navigation, and button clicks on the browser. Each supported browser in Selenium is paired with a distinct browser driver, which receives commands from Selenium test scripts and translates them for the respective browsers.
When a Selenium automation test is initiated, the process involves the execution of the following steps:
1. Each test command initiates the creation of an HTTP request based on the JSON Wire Protocol. This request is subsequently transmitted to the browser driver.
2. The HTTP request is directed through the HTTP Server for processing.
3. The HTTP Server facilitates the execution of the command on the actual browser.
4. The browser then transmits the test status back to the HTTP Server, which is tasked with relaying this information to the test automation script.
The browser drivers facilitate communication between Selenium automation scripts and various web browsers securely. They ensure that this communication occurs effectively while maintaining the confidentiality of the internal browser logic. Several commonly used browser drivers available in Selenium include ChromeDriver, FirefoxDriver, SafariDriver, OperaBrowser, EdgeDriver, and HtmlUnitDriver.
Real Browsers
A real browser is a software program or application for searching and seeing content on the World Wide Web. In the context of the Selenium WebDriver architecture in Selenium 3.0, the web browser component functions directly. The browser executes commands and invokes specific functions or methods to carry out the intended automation tasks.
Selenium supports nearly all widespread and modern-age browsers, such as Google Chrome, Apple’s Safari, Mozilla Firefox, Microsoft Edge, etc.
The Architecture of Selenium 4 WebDriver
The architecture of Selenium 4 closely resembles that of Selenium 3, with the notable difference of utilizing the W3C protocol in place of the JSON wire protocol for facilitating communication between Client Libraries and Browser Drivers. The WebDriver in Selenium 4 is fully compliant with the W3C standards.
In the Selenium architecture, all browsers and browser drivers adhere to W3C standards, except Selenium 3 WebDriver. As a result, the JSON Wire Protocol is utilized to encode and decode requests and responses. Selenium 4 WebDriver has been aligned with W3C standards to facilitate seamless and direct communication between client libraries and browser drivers. This enhancement in communication has contributed to increased stability in Selenium testing environments.
How does Selenium WebDriver Work Internally?
In a practical application, upon executing a Selenium script written in any programming language using a supported Selenium client library (such as Java), the web browser will open and begin executing the commands outlined in the script. Subsequently, let us understand the internal processes that transpire from the initiation of script execution to the launch of the web browser.
- When the Run button is activated, the Selenium client library executes Selenium commands from the automation script and translates them into a serialized JSON format. For instance, a command like navigating to “https://www.lambdatest.com” is serialized as {“URL”: “https://www.lambdatest.com”} using the JSON Wire protocol over HTTP. This serialized data is then sent to the browser driver (such as ChromeDriver) for each command. The browser driver uses an HTTP server to accept incoming HTTP requests.
- The JSON Wire Protocol facilitates communication between clients and servers by exchanging data. The browser driver receives HTTP requests from the HTTP Server, which executes various actions and commands on the browser driver. Subsequently, the browser driver initiates a request to load the specified URL on the real browser.
- Upon completion of all instructions and commands, the execution status is transmitted to the HTTP Server via the HTTP protocol. Additionally, the browser driver utilizes the HTTP server to receive the HTTP request and relay it back to the client library through the JSON Wire Protocol.
In Selenium 4.0, the JSON Wire protocol has been eliminated, allowing the browser driver to directly interface with Selenium client libraries for executing a range of commands on real browsers. By integrating the features of Selenium WebDriver with the versatility and accessibility of cloud platforms, testers can optimize their testing procedures and improve the overall quality of their applications.
An AI-driven test orchestration and execution platform like LambdaTest provides greater scalability and cost-efficiency compared to establishing an in-house Selenium Grid. It offers an online browser farm with over 3000 browser and operating system combinations for automation testing. To switch from local to LambdaTest’s cloud Selenium Grid, you must modify the infrastructure-related code in your test scripts.
LambdaTest includes the SmartWait feature, which addresses synchronization problems in Selenium. This feature improves the efficiency and precision of automated test execution by performing actionability checks before interacting with webpage elements.
Conclusion
Exploring deeply into the design and implementation of Selenium WebDriver offers a comprehensive understanding of its fundamental features. By exploring the complexities of this robust tool, professionals can effectively leverage its capabilities to develop resilient automation solutions. The versatile and dependable nature of Selenium WebDriver positions it as an essential resource in software testing, allowing developers to optimize processes and elevate product quality.
