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Testing plays an important role in the development cycle, ensuring the quality and reliability of your applications. It helps catch and fix bugs before they affect the users and confirms that the app works smoothly across different browsers and operating systems.
Several testing methods exist, including manual, automated, and performance testing. Automation testing, in particular, is favoured for its speed and efficiency. Selenium Testing is a widely used tool for automated testing because it allows one to write tests in different programming languages and run them on different browsers and operating systems.
This article will explore Selenium Testing and its components and share best practices to help you make the most of it.
Overview of Selenium
Selenium is a collection of tools and libraries designed for automation testing of websites and web applications. Selenium offers compatibility with multiple programming languages through language-specific drivers, including C#, Java, Perl, PHP, Python, and Ruby. Among these, Selenium WebDriver is particularly popular with Java and C#. Test scripts are adaptable to multiple programming languages and can be directly executed in contemporary web browsers such as Internet Explorer, Mozilla Firefox, Google Chrome, and Safari.
The Selenium suite comprises three primary components:
- Selenium WebDriver
- Selenium Grid
- Selenium IDE
Why Use Selenium for Testing Software?
Selenium is favored for software testing for several compelling reasons:
Language and Framework Support
- Supports major programming languages like Java, Python, JavaScript, C#, Ruby, and Perl.
- Each language has dedicated frameworks for writing Selenium test scripts.
- No need to learn Selenium-specific languages.
Open Source Availability
- Selenium is a publicly accessible and open-source tool.
- No upfront costs involved.
- Ability to customize code and enhance functionality.
Multi-Browser Support
- One Selenium script can be executed across different browsers (Chrome, Firefox, Safari, Edge, etc.).
- No need to rewrite scripts for each browser.
Cross-Platform Compatibility
- Selenium supports various operating systems (Windows, Linux, macOS, UNIX).
- Test suites can be created on one platform and executed on another.
Ease of Implementation
- User-friendly interface for creating and executing test scripts.
- Ability to watch tests running and analyze detailed reports.
- Extensive community support is available.
Reusability and Integrations
- Test suites are reusable across multiple browsers and operating systems.
- Integrates with third-party frameworks and tools (TestNG, JUnit, Jenkins, Maven, Docker, etc.).
- Extends testing capabilities through integrations.
Parallel Test Execution and Faster Go-to-Market
- Selenium Grid enables executing multiple tests in parallel.
- Cloud grids support cross-browser testing across hundreds of browsers simultaneously.
- Reduces overall test execution time.
Less Hardware Usage
- It requires less hardware than other vendor-focused automation tools.
Easy to Learn and Use
- Writing Selenium scripts is relatively simple.
- Extensive documentation and tutorials are available.
- Selenium IDE extension for record and playback functionality.
Constant Updates
- Active community ensures regular updates and upgrades.
- Updates are readily available and easy to understand.
- There is no need for specific training, making it cost-effective.
Components of Selenium
Selenium is a set of tools commonly employed to automate tasks on web browsers. It comprises various components tailored to specific functions in testing web applications. Here are the main components of Selenium and what they do technically:
- Selenium WebDriver
- Selenium Grid
- Selenium IDE
Selenium WebDriver
Selenium WebDriver is a part of the Selenium toolset for running or automating web app testing. It gives developers and testers an interface to create and run test scripts that mimic user actions with web browsers. These actions include clicking links, filling out forms, and retrieving page data. The scripts can run either locally or remotely.
When running Selenium tests remotely on a cloud grid, there is the Selenium RemoteWebDriver, which enables browser automation tests to be run on a cloud-hosted machine. Essentially, it’s a WebDriver version that executes on a remote server. Specific drivers for browsers like Firefox, Chrome, and Internet Explorer are built on top of the RemoteWebDriver class. This means they share core capabilities while being tailored to their respective browsers.
With Selenium 4.6.0, Selenium Manager was introduced to handle browser drivers behind the scenes, so users don’t have to worry about them directly. This streamlines setup by eliminating the need to manually download, configure, or update drivers for Chrome, Firefox, or Edge browsers. Instead, Selenium Manager ensures the correct, up-to-date drivers are always used.
Selenium WebDriver provides the language bindings and implementations for controlling specific browsers. In June 2018, WebDriver received an important endorsement by becoming a W3C standard protocol.
Selenium Grid
Selenium Grid, a vital component of Selenium, enables the concurrent execution of multiple test scripts across various browsers, operating systems, and machines. It operates on a hub-and-node architecture, with the hub as a central controller for a network of test machines (nodes). This setup enables distributed parallel testing, significantly reducing the time required for cross-browser and cross-platform testing scenarios.
The Selenium Grid 4 architecture is structured around four primary processes: Session Map, Node, Router, and Distributor. Moreover, the Selenium 4 WebDriver hierarchy boasts several enhanced features, such as an upgraded graphical user interface and integrated Dockey, augmenting its functionality for automation testing.
Selenium IDE
Selenium IDE is a Chrome, Firefox, and Edge browser extension that simplifies recording and executing tests directly within the browser environment. With its user-friendly interface and pre-built functionalities, it enables testers to rapidly create reliable tests without the need for additional setup or configuration.
One of the key advantages of Selenium IDE is its advanced debugging capabilities, which include features such as breakpoints and exception pausing. These debugging tools enhance the efficiency of the troubleshooting process.
Moreover, Selenium IDE supports automated cross-browser testing, enabling users to run tests across different browsers and operating systems using the Command-line Runner. This cross-browser compatibility ensures that web applications function significantly to improve a seamless user experience.
Best Practice for Using Selenium
Following are the best practices of Selenium for enhancing test coverage:
Running Parallel Tests with SIDE Runner
The latest version of Selenium IDE significantly improves on its predecessor by enabling parallel testing. This capability is vital for accelerating automated browser testing.
The latest version of Selenium IDE allows you to set up test suites to run tests concurrently by adjusting settings directly within the IDE. Furthermore, the SIDE runner further enhances this capability, making parallel test execution seamless. You can conveniently specify the desired number of parallel processes using the -w option, which governs the concurrent running processes. This improvement streamlines the testing process, leading to increased efficiency and faster test execution.
Selecting the Right Web Element Locator
Maintaining test relevance in Selenium automation can be challenging, especially when the locators within the test code undergo changes. Selenium WebDriver typically utilizes web locators such as ID, Name, LinkText, XPath, CSS Selector, and DOM Locator.
Selecting appropriate locators in Selenium is crucial to mitigating the effects of UI alterations on tests. LinkText is effective in dynamic scenarios, while ID, Class, and Name locators are simpler and tend to be more stable, reducing the likelihood of encountering issues.
XPath is sometimes necessary, but it can differ between browsers. It might also require a JavaScript XPath Query Engine for Internet Explorer, which can slow things down. XPath is more delicate because changes in page structure or new elements can break existing XPath implementations.
LinkText or partialLinkText might not work for applications with multiple languages if anchor tags lack IDs or classes. In such cases, using partial href is a good option to maintain consistency even when the site’s language changes.
The preferred order for web selectors is generally ID > Name > CSS Selector > XPath.
Utilizing Design Patterns in Selenium
When writing Selenium test automation scripts, ensuring they’re easy to maintain and can grow as your project does is vital. You want to minimize the impact of any UI changes on your test scripts. However, if your scripts aren’t well-organized and multiple scripts refer to the same web element, any change to that element would require updates in multiple places.
The Page Object Model (POM) tackles this challenge by creating a central repository for web page elements, with each page represented as a separate class. This way, scripts engage with web elements via an intermediary layer of page classes or objects. This structure simplifies maintenance, as changes to web elements only need to be made in one place, enhancing maintainability and reducing code duplication across multiple Selenium scripts.
Maximizing the Browser Window
Taking screenshots in Selenium is a typical part of test automation for troubleshooting and monitoring product development. However, by default, Selenium doesn’t open browsers in full-screen mode, which can affect the screenshots in test reports.
Maximizing the browser window after loading the test URL is important for getting complete screenshots of the entire page. This approach is advised for Selenium testing across various browsers.
Avoiding Sleep Calls that Block Execution
When doing Selenium testing, it’s best to avoid using sleep calls that block the thread, like Thread.sleep or time.sleep. These calls can pause the test thread, which might slow down the test execution. Also, they don’t always work perfectly because they depend on factors like network speed and server load.
Instead, using Implicit and Explicit waits in Selenium is more efficient. Implicit wait sets a default wait time for all elements throughout the test execution. On the other hand, Explicit wait, using WebDriverWait and ExpectedConditions, lets you pause the script execution based on specific conditions. This gives you more control and flexibility in handling delays. The script continues when the conditions are met or when a timeout or exception occurs.
AI-powered test orchestration and execution platforms like LambdaTest offer a SmartWait feature to tackle synchronization issues in Selenium. It enhances the efficiency and accuracy of automated test execution by checking if elements are actionable before interacting with them. LambdaTest is an AI-powered test orchestration and execution platform that lets you run manual and automated tests at scale with over 3000+ real devices, browsers, and OS combinations.
Creating a Cross-Browser Compatibility Matrix
Cross-browser testing can be complex as it involves choosing which combinations of browsers and operating systems to test. With various browser versions available, the potential combinations can be overwhelming. Hence, it’s crucial to establish a formal list outlining these combinations, including the browser, operating system, and device.
This structured list, often called the browser matrix or browser compatibility matrix, serves as a guide for prioritizing cross-browser testing efforts. It’s derived from a thorough product data analysis, user demographics, and insights into browser usage patterns. Additionally, statistical data, such as user distribution across browsers and competitive analysis, are considered.
By utilizing the browser matrix, you ensure comprehensive coverage of relevant browsers for your product. This strategic approach not only streamlines development and testing processes but also optimizes resources by focusing efforts on browsers that are most significant for your target audience.
Conclusion
In this detailed article, we looked at some of Selenium’s best practices, and ultimately, Selenium is a very useful tool for automatically testing web applications. Following good practices when using Selenium can help teams test their software better.
Some key good practices include running multiple tests at the same time, choosing the right ways to identify webpage elements, setting up code in an organized way, making sure the browser window is maximized, avoiding delays that pause the test, and making a list of all the browser/operating system combinations to test.
Doing these things allows Selenium to work its best for thorough testing, faster test runs, and ensuring high-quality software releases. As web technologies keep changing, it will be important for teams to stay up-to-date on new Selenium capabilities and follow proven methods for automated testing success.