In agile development, regression testing allows development teams to focus on new functionality while preserving product stability with each new product iteration. Teams do regression testing to ensure that tested software continues to function after each change.

Regression testing is the “stepchild” of agile testing, and while it is disliked by many, it is required to achieve the high velocity that agile teams aspire for.

Regression Testing In Agile Environment

Testing must evolve with each sprint in Agile, and testers must ensure that new modifications do not impair the application’s existing functionality. Regression testing is the term for this.

Regression testing verifies that the application’s previous functionality is still functional and that new updates haven’t introduced any new bugs. Instead, regression testing should be used whether there is a minor localized update to the software or a broader modification.

Teams must ensure that new code does not conflict with previous code and that non-changed code continues to function as planned.

There are numerous build cycles in agile, and the application is updated regularly. As a result, regression testing is critical in agile.

Therefore, a testing team should establish the regression suite from the beginning of product development for successful regression testing in agile. Along with development sprints, they should continue to improve them.

Importance of Regression Testing In Agile Development

In an agile framework, the team focuses on sprint-specific features. While the team is focused on one product area, they cannot be expected to consider the risks their changes may cause to the overall system.

A regression test will show areas affected by the team’s recent changes across the codebase if coverage is sufficient.

Regression tests should be done immediately after changes are made, preferably automatically as part of the build process. However, when input arrives later than expected, the team may have already begun modifying other system parts.

Regression Testing In Agile Methodology

Regression testing can be done in three different methods. First, your circumstances will determine your method, the size of your codebase, the number of testers on your team, and the available resources.

• Re-test everything, which entails rerunning all existing tests against the updated source. This would isolate regressions if the tests were well-designed. This strategy, however, consumes a lot of resources and may not be feasible for a massive codebase.
• Selective re-testing—occasionally, it’s possible to find a subset of your existing tests that can cover all or nearly all of your codebase’s “moving parts.” It’s only a matter of rerunning that select set to find regressions throughout the codebase.
• Re-testing is prioritized and is utilized on huge codebases. Priority tests focus on code routes, user activities, and areas of functionality that are likely to have defects. After completing these tests, you can move on to the remaining tests.

Regression Testing In Agile Scenario

Regression testing, on its own, ensures that past functionality continues to perform as intended after the inclusion of a new feature. In an agile development method, regression testing ensures consistent results at the end of each sprint by evaluating the impact of newly produced segments on the application, assuring the overall system’s smooth operation.

New features are introduced every sprint in an agile development process, and the regression test suite should be kept up-to-date at all times to guarantee that all parts are working correctly after each sprint.

Test cases corresponding to all previously tested and stable features should be introduced to the test suite regularly, and test cases that are no longer relevant should be removed. All of the test cases that need to be modified to reflect additional new functionalities should be done.

As a result, for effective regression testing in an agile environment, a testing team must generate regression test suites from the beginning of the development process and continue to build them as the sprints progress.

Before starting regression testing, you must first create a regression test plan. Here are a few phrases that are crucial in this process:

• Test cases are chosen for execution
• Identifying improvements for re-designing test cases.
• Estimating the time it will take to run a regression test and laying out the test cases that will need to be automated in the regression test plan.

When To Do Regression Testing In Agile

It may take trial and error to get the correct cadence for running your entire regression testing suite. However, not every change in your code is significant enough to warrant executing your complete suite.

However, because you’ll be more familiar with the features in the new version and the volume of code you’re testing is lower, the more frequently you run the suite, the less time it will take to review the results and correct any errors

Every time you merge a branch back to master, you should run your whole regression suite. If that isn’t practicable, there are a few general guidelines to follow. In the following scenarios, you should always run your regression suite:

• When it comes to adding new features to a product (for example, adding time-tracking to an invoicing app).
• After resolving flaws in an existing feature, check if the bug fixes caused any new regressions.
• Following the implementation of a significant software upgrade (for example, switching to the latest version of Ruby on Rails).
• Before releasing code to the public.

Regression Testing Strategy In Agile

#01 Using Sanity And Smoke Test Cases
Testing teams can save time by performing smoke and sanity tests before regression tests. However, before the extra testing of a new release, sanity testing is a run-through of an application’s basic functionality, which informally checks that functionality works as expected.

To execute smoke testing, you’ll need a subset of test cases that can quickly run and test primary and core product workflows, including startup and login.

Sanity tests and smoke tests can be used to quickly determine whether an application is too faulty to require further testing, such as regression testing.

This is far preferable to running regression tests on a product that doesn’t load or allow login and then attempting to figure out why hundreds or thousands of regression tests are failing.

#02 Identifying Places That Are Prone To Errors
Include the most often failed test scenarios. Some parts of the application are so prone to errors that even simple coding changes can cause them to fail.

For example, you can keep track of these failing test cases during the product cycle and put them in the regression test suite.

#03 Prioritization Of Test Cases
In a risk-based approach, a testing team picks test cases that cover the application areas most affected by project modifications. They also assign a priority to them. For example, regression testing concentrates on product categories with the highest perceived risk of quality problems.

Prioritize the test cases based on the most important and commonly used features. For example, you may decrease the regression test suite, save maintenance work, and run regression tests faster and more frequently by selecting test cases based on their priority.

#04 Investigating Bug Reports
Some regression testing software works in tandem with error-tracking software. This gives you detailed information about what happened during a regression test; such as if it failed, why it failed, and which line of code was affected.

During regression testing, error tracking tools can also help you get screenshots and other analytics about failures; which can help you discover and debug the problem.

#05 Communication
To track and assess changes in requirements, testers should communicate with product owners. In addition, they should connect with developers to figure out which modifications were done during each iteration.

Agile Regression Testing Best Practices

Testers must be included in agile teams from the start of each sprint. This is because to structure tests and maintain them up to date right from the start.

Every time changes are made to the software under development. Regression test suites must be updated. After each sprint, they review it to streamline quality assurance, removing obsolete test cases and adding pertinent ones.

Automation is non-negotiable if you speed up regression tests for Agile sprints. Begin with an automated regression test script, then tweak it when new features are added. As a result, QAs must focus on making incremental changes with each sprint rather than running the tests.

Challenges of Regression Testing in Agile

#01 Expanding Regression Test Suites
As new features are added, the size of regression tests grows. However, the suites can soon grow cumbersome and unmanageable if there isn’t enough automation and team organization.

#02 Communication Requirements
Testers must communicate with developers, business analysts, users, and other stakeholders regularly. They require this to become acquainted with the features being developed and user expectations. This may be challenging to achieve and maintain for small teams in particular.

#03 Test Case Maintenance Pressures
As test suites grow, they must be maintained, inspected, and updated after each sprint. Tests that are no longer in use must be removed, and new tests must be created and added. If a project necessitates many iterations, this might be tedious.

Conclusion

Regression tests are an essential part of any development process since they ensure that incremental development does not disrupt the program at any point.

Therefore, to create defect-free, high-quality user experiences in competitive schedules, designing and executing regression testing to adapt to Agile needs combines the best of Agile principles with the safeguarding mechanisms of extensive testing.

Source: This article was originally published at testgrid.io