Web Browser Online: Parallel Test Execution

As technology advances, organizations increasingly transition from manual testing to Selenium automation testing, enhancing scalability and efficiency. However, many still struggle with implementing parallel testing for web browser online environments, relying on resource-heavy, sequential methods instead. Selenium Grid addresses this challenge by simplifying parallel testing, making it an essential tool for robust quality assurance processes.

In this blog, we’ll delve into the importance of parallel testing in accelerating release cycles. We’ll start with its core principles, explore how it improves test execution, and share practical tips on effectively implementing parallel testing strategies for web browser online scenarios.

What is Parallel Testing?

Parallel testing is a software testing approach that allows you to run your multiple test cases or test suites simultaneously across various testing environments across various browsers, real devices and OS configurations. Unlike sequential testing, parallel testing significantly reduces testing time, making it an efficient solution for handling large test suites.

Why is Parallel Testing Important?

Let’s consider a scenario involving sequential execution. Suppose we need to test the functionality of a signup form and have written an automation test script. If we aim to execute this test across three different browsers, where the Chrome test takes 3 minutes, the Firefox test takes 4 minutes, and the Edge test takes 5 minutes, the total execution time in a sequential approach would be 12 minutes.

Now, imagine extending this testing process to other modules, such as the pricing page, demo scheduling form, contact form, and more. Even with automated Selenium test suites, running tests one after the other could result in an exceedingly long execution time.

However, by adopting parallel testing in the same scenario, we could execute the browser tests simultaneously, reducing the total execution time. This approach not only saves time but also enhances the efficiency of the continuous integration and continuous delivery (CI/CD) pipeline by dividing extensive test suites into smaller, independent jobs and running them concurrently. As a result, testers gain faster access to detailed test reports, allowing development teams to identify and resolve bugs swiftly, further optimizing CI/CD performance.

Nevertheless, it does come with challenges, such as coordinating tests to avoid interference. This is particularly relevant in distributed testing, where test cases are executed across multiple machines to enhance test coverage and reduce testing time. While distributed testing allows for interaction between test parts, careful management is crucial to maintain efficiency and accuracy.

When to Execute Parallel Testing in Selenium?

Now that we understand how parallel testing in Selenium enhances the continuous integration and delivery of applications, it’s important to explore when and how to incorporate it into the Software Development Life Cycle (SDLC). Parallel testing is particularly beneficial in the following scenarios:  

• Banking and financial applications: In industries like banking, where applications often share similar functionalities, parallel testing in Selenium can validate both earlier and newer versions of an application effectively.  
• Data migration tasks: When legacy data is being imported from one system to another or a company transitions from an old system to a new one, parallel testing ensures the integrity and accuracy of the migration process.  
• Application updates: For applications receiving updates that closely resemble previous versions, parallel testing streamlines the verification process by efficiently comparing functionalities.  
• Regression testing: By running tests concurrently across different features or modules, parallel testing accelerates regression testing efforts and ensures comprehensive validation.  
• Large test suites: For test suites containing numerous test cases, parallel testing significantly reduces execution time by running multiple tests simultaneously, improving overall efficiency.

How to Approach Parallel Test Cases in Selenium?

While performing parallel testing in Selenium, it’s essential to adhere to specific steps for efficient execution. These steps include:

1. Identify Testable Components

Identifying testable components involves dividing the software application into separate units or modules that can be tested independently and in parallel. This approach enables the identification of areas suitable for concurrent testing, fostering more efficient and streamlined testing strategies. These components can include individual features, modules, or even standalone applications within a larger system. 

Examples of such testable components include login functionality, user registration, shopping cart operations, and payment processing.

2. Design Independent Test Cases

Creating independent test cases is essential for ensuring the effectiveness of parallel testing. Each test case must be self-contained and free from dependencies on other test cases or external factors. This approach allows tests to run simultaneously without the risk of interference or inaccurate outcomes. 

By designing such independent test cases, testers can achieve genuine parallelism, maximizing resource efficiency and significantly reducing testing time.

3. Allocate Test Environments

Allocating test environments requires using multiple machines or setups to run parallel tests simultaneously. To ensure consistency and reliability, it is crucial that each environment shares identical configurations, operating systems, and dependencies. 

Standardizing these test environments reduces variability, ensuring the application behaves consistently during testing. This approach enhances the accuracy and dependability of the results obtained from parallel testing.

4. Manage Test Data

Effective test data management is crucial during parallel testing to avoid conflicts and ensure accurate outcomes. It’s important to prevent situations where multiple tests access or modify the same data simultaneously, as this can cause errors or inconsistencies. To overcome this challenge, testers can use separate databases or generate unique datasets for each parallel test execution. Isolating test data for each test instance helps minimize the risk of data interference or corruption, ensuring reliable and consistent results throughout parallel testing.

5. Implement Test Synchronization

Synchronization is vital during parallel test execution, particularly when coordination between tests is required. For example, if one test case relies on the output of another, synchronization ensures the tests run in the correct order.

Techniques like locks, semaphores, or messaging systems can be used to manage parallel test execution efficiently. Proper synchronization helps maintain the accuracy of test results by addressing dependencies effectively, thereby improving the reliability and consistency of parallel testing processes.

Entry-Level and Exit-Level Criteria

An effective way to perform parallel testing is by creating separate projects for testing different parts of a web application across various browsers and then managing these projects through a master project. Typically, parallel testing in Selenium follows two main criteria: Entry-level criteria and Exit-level criteria.

Entry-Level Criteria

In entry-level criteria, specific tasks are defined that should be satisfied before executing tests in parallel successfully, such as :

• Set up a testing environment before initiating parallel testing in Selenium.  
• Clearly define preconditions and test scenarios prior to starting the automated browser testing process.  
• Ensure successful migration of both new and legacy data.  
• Select a parallel testing framework that best fits the project requirements.  
• Examine the application architecture and identify test suites suitable for parallelization. 

Exit-Level Criteria

The Exit level criteria describe the steps for executing parallel testing successfully, which include:

• Comparing the performance of old systems with newly developed ones.  
• Identifying differences between the old and new systems.  
• Executing the entire automated browser testing process using identical inputs.  
• Evaluating the output of the new system in comparison to the old system.  
• Reporting any identified bugs to the development team for resolution.  
• Assessing the effectiveness of the parallelization strategy to confirm it delivers the intended benefits.  
• Managing shared resources efficiently to avoid conflicts during parallel testing.
• Conducting a final review with stakeholders to evaluate the success of the parallel testing efforts. 

Tools for Parallel Test Execution

We can use various tools for parallel testing to facilitate concurrent execution of test cases across multiple environments or machines, enhancing testing efficiency and scalability. Some of the top tools are as follows:

1. LambdaTest

LambdaTest is an AI-powered test orchestration and execution platform that enables manual and automated testing at scale across over 3,000+ real devices, browsers, and operating system combinations.

It is an excellent choice for parallel testing, offering a cloud-based Selenium Grid that allows tests to run simultaneously across multiple browser and device combinations. With seamless integrations with popular testing frameworks and CI/CD tools, LambdaTest enhances parallel testing workflows, allowing you to also use AI testing tools like KaneAI that allows you to generate, create, and deploy test cases and lets you run across multiple browsers, making it a versatile solution for efficient test execution.

Key Features:

• It provides a cross-browser testing solution to test web apps across diverse browsers and devices simultaneously.
• It seamlessly scales test execution with Selenium Grid integration.
• It provides visual UI testing to detect visual discrepancies and ensure consistent UI rendering.
• It conducts live interactive testing on real browsers and devices.
• It captures automated screenshots to detect visual regressions.
• It executes parallel testing concurrently across multiple environments for faster results.
• It provides a Single sign-on(SSO) authentication feature to access multiple applications with one set of login credentials.
• Its scalable infrastructure dynamically allocates resources to handle varying testing demands, ensuring high performance and cost efficiency.
• It provides a facility for Real-Time Testing and Real Device Testing.
• It allows us to test websites in different locations by providing a cloud of 3,000+ real devices and desktop browsers with geolocation testing.
• It offers various intеgration options with tеam collaboration tools to strеamlinе our softwarе tеsting and dеvеlopmеnt procеssеs.

2. Appium

Appium streamlines parallel testing by enabling testers to run automated tests concurrently on multiple devices and platforms. Its server architecture provides native support for parallel execution, allowing tests to be executed simultaneously on different devices or emulators. Appium also supports distributed testing by connecting to multiple servers, optimizing resource usage and accelerating test execution. Additionally, with Xcode9, Appium supports parallel testing on both real devices and simulators, making it an efficient choice for conducting parallel iOS tests.

Key Features:

• Allows testing of native, hybrid, and mobile web applications across various platforms such as iOS, Android, and Windows.
• Provides native automation APIs for each platform.
• Supports testing on real devices as well as emulators and simulators.
• Offers integration with cloud-based testing platforms.

3. TestNG

TestNG simplifies parallel testing with its built-in capabilities to execute test cases simultaneously across multiple threads, classes, or suites. It provides various parallel execution modes, including methods, classes, and tests, enabling testers to optimize test distribution effectively. Moreover, TestNG handles thread safety and ensures proper synchronization, allowing for seamless implementation of parallel testing while minimizing concurrency-related challenges.

Key Features:

• Allows testers to specify parallel execution at different levels, including methods, classes, and test suites.
• Manages thread safety and synchronization automatically.
• Enables customization of the thread pool size.
• Offers various parallel execution strategies to cater to different testing requirements and scenarios.

End Note

In today’s fast-paced digital world, parallel test execution in web browser online environments is essential for delivering reliable and efficient web applications. By running multiple tests simultaneously across browsers and devices it reduces execution time, enhances coverage, and improves test accuracy.

With careful planning and execution, parallel testing streamlines workflows strengthens CI/CD pipelines, and helps teams deliver high-quality applications faster. Embracing this approach is key to ensuring seamless user experiences and staying competitive in modern software development.