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Why do we have to run Selenium tests in parallel?

What are the reasons to run Selenium tests in parallel?

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Posted 4 months ago


What Is Parallel Testing And Why To Adopt It?

With the advancement in technology, testing solutions have become more scalable than ever, as organizations moved to Selenium test automation from manual testing. But, one area that most organizations are still struggling with is the scalability to run multiple tests in parallel. Many corporations are still using sequential testing methods to deliver quality assurance, which consumes a lot of time, resources, and efforts. Some are either reluctant towards the implementation of parallel testing in Selenium while others are probably not doing it because their web-application is small enough to be managed by the current release windows. Keep in mind though, every release is bound to expand the web-application, and somewhere down the road, you are going to hit a hard brick wall if you don’t adopt for parallel testing. Not to forget, the primary reason for the existence of the Selenium Grid is to allow testers to run test cases in parallel.

This article is my attempt to help you realize the importance of parallel testing in your next release cycle. I’ll talk about parallel testing in detail, ranging from the definition to best practices for parallel testing in Selenium, we will talk about it all to help you scale your testing efforts. Without further ado, let’s start!

What Is Parallel Testing In Selenium Automation? Parallel testing in Selenium is a process where you run the same tests simultaneously in different environments. The primary purpose of executing tests in parallel is to reduce the overall time and efforts of automated browser testing while ensuring a quality product by using a Selenium Grid.

Let’s take a test scenario of sequential execution.

Say, you want to test the functionality of a signup form, you’ve written then automation test script for the form. If you wanted to perform this test over 60 different Browser and OS combinations, and let’s say your single test runs in 2 minutes, you’d take a total of 120 minutes i.e. 2 hours. And this is only the sign-up form, what happens if you were to run automation scripts over other modules such as pricing page, demo scheduling form, contact form, and more! Even if you automate your Selenium test suites, if you run them one after the other, it is going to take forever for your tests to complete.

Now, what would happen if you were to run 3 parallel tests simultaneously, in the above scenario?

You’re right! The total execution time would have trimmed down from 120 minutes to just 40 minutes. Similarly, if you had 4 parallel tests running, the total time would have chopped down to 30 minutes only and so on.

Why To Run Selenium Tests In Parallel? There are various reasons that make it crucial for testers to adopt parallel testing in Selenium as their first automated browser testing approach. Some of the most popular reasons are:

Wide Test Coverage Executing tests in parallel is a faster approach than sequential testing, as it provides testers with wider test compatibility in less span. For example, if you want to test the user interface functionality of a new web application, then you don’t have to run tests again and again for different OS and browser combinations, you can test all the combinations at the same time by running tests in parallel.

Reduce Testing Time Sequential testing does provide a comprehensive and thorough automated browser testing of an web application, but it is very time-consuming. On the other hand, parallel testing can reduce the overall testing time by running tests on multiple machines in parallel. For example, if you want to run 100 concurrent tests, then you can reduce the automated browser testing time by a factor of 100, which in turn helps you deliver the product more quickly.

Cost-Effectiveness Sequential testing requires developing, maintaining, and keeping the test environment up-to-date, which can affect your overall budget. But parallel testing in Selenium is an automated process that runs on the cloud, so there is no need for maintenance. Moreover, you don’t have to worry about the updates, as the cloud infrastructure is always updated.

Optimize Continuous Integration And Delivery For continuous integration and continuous delivery, you need to run functional tests frequently and quickly. And if you run tests in parallel, it will not only buy you more time but also allows you to have detailed reports of test data. Development teams can later use these reports to find issues in the code and fix them quickly in order to optimize CI/CD.

Continuous Testing A great way to release high-quality products in the shortest time possible is using continuous integration and delivery methodology. Continuous testing requires a faster test cycle, which is not feasible with sequential automated browser testing. However, if you use parallel testing in Selenium that allows you to leverage the cloud and virtualization to perform more tests at a faster speed, then you can release products more quickly to the market.

How To Implement Continuous Testing In DevOps Like A Pro?

When Should You Execute Parallel Testing In Selenium? Now, you know how parallel testing in Selenium is helpful for continuous integration and delivery of applications, it’s time to understand when and how you should implement it in your SDLC. You can use parallel testing for the following scenarios:

  • If there is even minimal uncertainty in the functionality of new applications, especially when the updated and earlier version of the app is similar.
  • For financial applications related to the banking sector, where most applications are identical. Parallel testing in Selenium can be used to verify the earlier and newest versions of the application.
  • While importing legacy data from one system to another, or a company moving from old system to new system.
  • During automated browser testing, when you need to test an app across multiple combinations of browsers, operating systems, and devices.

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Posted 4 months ago