Best Practices for Selenium Test Automation

With constant advancements in digital technologies, web-applications are becoming increasingly sophisticated. This translates to new challenges for QA engineers as they need to perform comprehensive testing of new features across platforms.

Bear in mind that delivering a flawless user experience is mandatory for any website to succeed in the current-day competitive landscape.

Reliable and established open-source tools like Selenium have made it possible for QA engineers to minimize manual testing. They also enable the execution of comprehensive tests faster. However, to get efficient results from Selenium tests, one must be well acquainted with the relevant best practices.

This article will highlight a few of these best practices that will help QAs enhance their Selenium tests.

Best Practices For Selenium Automation

Here are some of the core Best Practices for Selenium Automation:

1. Using the Right Locators

For testing the desired web elements of a particular application, QAs need to be proficient in using different locator strategies. After all, if the test scripts cannot identify the correct elements, the tests will fail.

Example: For automating inputs to the Username and Password fields of a login page, the primary step is to locate those text fields. If the script cannot find the Username and Password fields, the login process will not work.

Refer to this detailed guidepost on Locators in Selenium to understand different ways to locate web-elements and which locators are best suited for which situations.

2. Implementing Page Object Model

With ever-increasing customer demands, a website’s UI is bound to evolve after incorporating new changes at regular intervals. Needless to say, locators corresponding to specific UI elements change too. This means QAs need to create new test cases for the same page again, which can be tedious.

One can address this by using the Page Object Model design pattern for creating test scripts. In this design pattern, each web page is considered a class file, and every class file carries corresponding web elements. This technique helps eliminate code duplication and also makes test maintenance more convenient. QAs can also reuse the existing code and make minimal changes.

3. Running Selenium Tests on Real Devices

Although there are multiple emulators available on the internet for Selenium testing across platforms, running tests on real devices makes a considerable difference.

Emulators are just software programs that mimic the functionality of a device. They are more suitable for testing code changes in the initial stages of development. Besides, emulators for each device-OS combination may not be available, which makes it even more challenging for QAs to test on desired combinations.

Accurate results can only be expected when websites are tested in real user conditions. This allows teams to discover maximum bugs and eventually roll out a robust application.

Teams can leverage cloud-based platforms like BrowserStack that offer a Cloud Selenium Grid of 3000+ real browsers and devices.

It empowers teams to run concurrent Selenium tests on desired device-browser combinations online. This makes it convenient for QA engineers to perform comprehensive cross-browser and device testing across platforms. One can also integrate their test pipelines with CI/CD tools like Jenkins, Travis, Circle CI, etc.

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4. Take Screenshots when a Test fails

It is inevitable that Selenium scripts will fail at some point or another. A major issue in this regard is figuring out why the failure occurs – a bug in the AUT or an error in the code.

To remedy this, set up the test infrastructure to take screenshots whenever a failure occurs. This will make it much easier to investigate and identify the cause of test failure, saving the testers’ time and effort.

BrowserStack’s Cloud Selenium Grid allows testers to take screenshots automatically during Selenium tests without having to initiate the process specifically via code.

5. Use the Browser Compatibility Matrix

To start with, it is a challenging task to narrow down a list of browsers (browser versions, too) and operating systems to run automated tests on. To manage this task, it is recommended that you use a browser compatibility matrix.

A browser compatibility matric draws vital data from multiple metrics – browser, device, and OS usage numbers, product analysis, target audience preference, and more. It then limits test coverage to a specific set of browsers and devices. Essentially, it restricts the scope to the most relevant browser-OS combinations, thus making the process more manageable

6. Incorporating Wait Commands

Web browsers take some time to load individual web pages. The page load speed is subjective to network conditions, server issues, or system configurations. To deal with this, QAs often use the Thread.sleep() method, which pauses the automation script for a specified amount of time.

However, this is not the most efficient method. In some cases, a website may take longer to load than the specified time. On the other hand, a website may load quicker than the specified time, resulting in slower test execution. A better, more efficient alternative is to use Implicit or Explicit Wait Commands in Selenium.

7. Planning and Designing Test Cases beforehand

QA teams must have a proper test plan in place before getting started with automation. QA engineers must think about all logical scenarios and create extensive test cases from the end-users’ perspective. Diving straight into automation without a concrete strategy usually leads to bottlenecks in the later stages.

Often, QAs focus more on verifying whether the scripts run successfully rather than planning for extensive test scenarios. This approach is ineffective for ensuring full-proof testing of web applications.

8. Identifying and Prioritizing Test Cases

Testing complex web applications can be challenging at times. Prioritizing certain test cases over others makes it easier to achieve test coverage goals. QAs must have clarity on which test cases are critical and need to be executed on priority.

Example: A login page is a vital part of any web-application. Naturally, automating tests to verify the login page makes sense. This is because the login page rarely undergoes any modifications but offers an important function. Thus, testing it would be easy, and running the tests would cover a high priority task in the pipeline early on.

Selenium automation seeks to reduce manual testing efforts, increase execution speed, and identify the maximum number of bugs at the earliest. However, in order to get the most out of their Selenium scripts, QAs must follow the selenium best practices highlighted above. This will also help in establishing a reliable test cycle.

9. Set Browser Zoom to 100%

Ensure precision in Selenium automation by setting the browser’s zoom level to 100%. This guarantees accurate mouse interactions at the correct coordinates, mimicking native behavior.

This is crucial for cross-browser testing, especially on older browsers like Internet Explorer, where incorrect zoom levels can disrupt element identification.

Additionally, ensure Protected Mode Settings are consistent across all zones in Internet Explorer to avoid issues such as the NoSuchWindowException.

10. Maximize Browser Window

Maximize the browser window immediately after loading the test URL to capture full-page screenshots effectively. By default, Selenium does not open the browser in maximized mode, which can result in incomplete or cropped screenshots.

Maximizing the window ensures that the entire webpage is visible and accurately captured, aiding in debugging and providing clear reports to stakeholders.

11. Leverage Parallel Testing in Selenium

Parallel testing is a key feature of Selenium that speeds up test execution by running tests simultaneously across multiple configurations. This improves coverage and helps identify browser-specific issues early.

Cloud-based platforms like BrowserStack Automate enhance this capability by offering scalable infrastructure for seamless parallel testing across various environments.

12. Avoid Code Duplication (or Wrap Selenium Calls)

Reduce code duplication in Selenium automation by creating reusable APIs for commonly used elements, such as web locators. This approach minimizes code bloat and enhances maintainability, making complex test suites easier to manage. Wrapping Selenium calls ensures your test code remains clean and efficient.

13. Use Headless Browsers for Faster Execution

To accelerate test execution, particularly for backend and API validation, use headless browsers like Chrome Headless or Firefox Headless. These browsers run without rendering a UI, which significantly reduces execution time while still allowing for effective functionality testing.

14. Avoid Hardcoding Test Data

Hardcoding test data in scripts makes them inflexible and difficult to maintain. Instead, use external data files (e.g., CSV, JSON, Excel) to manage test inputs.

This approach supports data-driven testing, allowing you to easily update test data and run tests across multiple datasets.

15. Use Assert and Verify Appropriately

Utilize assertions to halt test execution when a critical failure occurs, such as an incorrect locator affecting essential elements like the Gmail sign-in box. Assertions stop the test immediately, preventing further execution under faulty conditions.

Use verification for less critical issues where test execution should continue, allowing minor errors to be handled without interrupting the entire suite.

16. Avoid Using a Single Driver Implementation

In Selenium automation, avoid relying on a single WebDriver implementation, as WebDrivers are not interchangeable. Tests may use different WebDrivers locally versus on a continuous integration server.

Use parameterized tests to manage various browser types and enable parallel testing, ensuring your test code is flexible and scalable across different environments.

17. Perform Regular Test Maintenance

Regular maintenance of Selenium test scripts is essential as UI elements and functionalities evolve. Schedule periodic reviews and updates to prevent test failures due to outdated locators or changes in the application flow, ensuring ongoing test reliability.

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18. Use Data-Driven Testing for Parameterization

Enhance test coverage and quality by adopting data-driven testing with parameterization. Instead of hardcoding test values, use parameters to run tests against various input combinations.

This method reduces code bloat and allows comprehensive testing across different datasets, making your Selenium automation more effective and scalable.

19. Follow a Uniform Directory Structure

Organize your Selenium test automation project with a clear directory structure. Typically, a project includes a Src folder for the automation framework with subdirectories for Page Objects, helper functions, and locators, and a Test folder for actual test implementations.

A consistent directory structure enhances maintainability and clarity, making it easier to manage test code.

20. Use BDD Framework with Selenium

Behavior Driven Development (BDD) enables writing test cases in plain language (Gherkin), allowing both technical and non-technical team members to contribute.

BDD frameworks, such as Cucumber, Behave, and SpecFlow, bridge the gap between business and technical teams, improving test relevance and quality.

BDD tests, with standardized formats and keywords like Given, When, and Then, adapt easily to changes and offer better longevity compared to Test Driven Development (TDD).