How to Reduce Regression Testing Time 

Small changes can have big consequences. That is why teams do regression testing. Regression testing ensures that code changes do not break anything. It catches bugs early on in new builds.  

Regression testing can be time and resource-consuming. But it doesn’t have to be that way. Here is a guide for performing faster regression testing:  

Why Is Regression Testing Important?  

Regression testing verifies if the recent changes — either to the program or code — negatively impact the existing features of the software. It is a crucial tool for software developers because it allows them to analyze problems caused by new programming code into existing apps or programs.  

Agile regression testing ensures continuous, high-value regression tests, which allows teams to focus on new functionalities. To achieve this, teams must build regression testing suites with a focus on robust test scenarios, high coverage, and near-zero test maintenance. 

Related reading: What Is Regression Testing? >>

How to Reduce Regression Testing Time 

Some best practices to reduce regression testing time include:

• Improving your strategy.
• Testing in parallel.
• Setting up a reliable testing infrastructure.
• Analyzing failures & reviewing feedback.

There are many ways to go about regression testing, but some are more time-consuming than others. Reducing your regression testing time is crucial in order to keep up with release cycles and your competition. 

Let us explore some of these regression testing best practices more closely:

Improving Your Strategy  

It is crucial to have a well-defined and thought-out process when automating a regression testing suite. Staying organized and building a comprehensive strategy will also help regression testing go faster. 

Here are a few questions to ask when building out a software regression testing strategy:  

• What tests should be a part of your automated regression testing suite? Which ones should be manually tested? 
• If a test is not going to be automated, should it be left off of the regression suite? 
• When should automated test cases be produced throughout the sprint? 
• Who on the team is responsible for maintenance?  
• Who is responsible for excluding flaky tests when they are inconsistent?  
• How do we evaluate the outcomes? 
• When should I retire a regression test scenario? 
• Who is responsible for updating the test environment and lab with the most updated platforms and test data? 

To begin the process of speeding up your regression tests, it is essential to understand your organization’s current testing capacity. The Coverage Cube can help you measure your testing depth.  

The Coverage Cube measures quality on three axes: platform coverage, test cases, and user conditions. The metrics from the Coverage Cube show how long it takes to run your regression testing suites.  

• X-axis: Platform coverage. It is critical to test your app on different platforms to guarantee that it works on a range of devices and browsers.  
• Y-axis: Test cases. The axis refers to factors like the duration per test case, the proportion of automated tests in your suite, and the number of test cases your team has. 
• Z-axis. User conditions. There are additional things to consider for each platform you are testing on including location, network, and background applications. These extra elements can help you gain a better grasp of your platform's baseline. 

In between software releases and market changes, this cube changes over time. By finding out your current testing capacity, you can identify the lowest common denominator to begin the journey to better regression testing.  

Executing Your Plan 

Before adding more test cases to the regression suite, it is a good idea to run and validate them numerous times. This confirms that things function as they should because false failures waste time. 

When you are confident in your test suite's results you should bring the test cases together into a larger test suite. Test suites are created to test a single component from start to finish. This means that all the tests related to that component are consolidated into a single test suite. 

To execute these tests in parallel, you must make sure you have the right infrastructure set up and a CI box that can handle a high amount of parallel test execution. 

Infrastructure Setup  

The objective is to keep the test suite's execution time as short as possible. Now that you have a suite of individual tests, executing the entire suite at once should not take any longer than executing the slowest test.  

Each user interface test should have its own browser instance. It is up to you whether you want to create your own Selenium grid, use a Selenium grid in the cloud, or run on your CI server.   

Scale Your Test Automation With Parallel Testing 

To drive faster feedback at a higher scale, it is important to employ a CI server, like Jenkins, that is capable of handling the load of parallel test execution. Here are some common challenges and solutions as you get started:  

Challenges 

• Hundreds of simultaneous browsers or devices are used to perform tests, which cannot be done on a single CI computer because of its constraints.  
• False alarms—If the CI machine is overburdened, tests will fail. 
• When testing is carried out on a distributed system, it requires more effort. 

Solutions 

CI tools have a host-node option, allowing you to scale up your testing capability. 

• Build a host-node set up on each system and specify the number of executors.  
• Now run your tests on separate slaves at the same time to avoid an overload problem on the master system. 
• Brake down your jobs into smaller tasks – that will contribute to both the stability of your pipeline as well as to the debugging of a failed build. 

Analyzing the Failures 

Analyzing failures and creating plans to avoid them in the future is an important, but frequently overlooked, part of a test automation strategy. 

It takes much longer than teams expect for a tester to find out about a failing test case. As a result, release cycles may be pushed back, and an agile team slows down. 

To fix your failed scenarios, you need a comprehensive reporting and alerting system that includes the following features: 

• A central system for data collection  
• Stack trace for failed tests   
• Test and suite execution times 
• Alerting with build results 
• Several passed and failed cases 

Tests can also fail without an error in the application code, which is called flakiness. Here are some of the problems that create flakiness and how to isolate them. 

Flaky test scripts 

• Log the execution history of each test case. 
• Rerun failed tests cases manually or automatically to filter out flakiness.  

Test Code Design  

• Use best practices like Page Object Model (POM), Singelton, and others. 
• Log failures with test data and other relevant details.  
• Perform ongoing peer reviews of your test code, treat test code as production code 

Poor browser stability 

• Start Selenium session failures.  
• Page load failures.  
• Stale Selenium elements. 

CI server problems  

• Issues with dependencies and code checkout issues. 
• Memory and CPU difficulties with the CI machine. 
• Issues with network connectivity. 

We recommend that your reporting be centralized so that all cases can be evaluated from a single screen.  

Reviewing Feedback  

Once you have created your regression testing automation technique, double-check that it has been approved by everyone in the development team. 

From there, create a culture of continuous learning. Incorporate and embrace feedback from stakeholders, colleagues, and all team members that work with automation, and adjust the strategy as needed. 

Reducing Regression Testing Time With Perfecto  

So, what is next? 

After you have a good idea of how you want to approach automated regression testing and attempt to plan the automation road ahead of you, the next step may be to pick the right regression testing automation technology. 

Perfecto can help you leverage automated regression testing — and test more, faster. Know why tests failed and fix them quickly with Perfecto’s test reporting. See all your test results in one unified place — including a CI dashboard, heatmaps, and individual test reports. Rich artifacts like screenshots, videos, HAR files, and vitals help you understand what went wrong. And ML-powered noise filtering keeps you focused on real defects, not noise. Register for a live, engineer-guided demo of Perfecto or reach out for a custom demo.  

Regression test suites maintain the sanity of your application (and your team). However, they have the potential to devolve into a chaotic mess. It is up to you to keep improving your regression testing and reducing the time spent testing.  

The Bottom Line 

Try Perfecto’s all-in-one cloud testing platform. See how easy it is to create, execute, and analyze tests. 

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