Software Regression Testing-Build Regression Suite Guide Free

-Dennis Stevens from LeadingAgile

When we modify any part of how one service talks to other services, it tends to introduce a breaking change in the system if all the other dependent services are not updated. This is a serious problem devs and EMs are looking to solve. 

Since in the race to put the best version of their application to end-users, engineers are actively making changes to the apps–introducing new features, modifying based on user’s feedback etc.

• Some teams are deploying changes on a day-to-day basis, i.e the Kanban way

• Others are also following a sprint of 15 days or 1 month, but all are in the same race to be agile without breaking things

However, at this pace, issues are inevitable, and the code sometimes "turns red." Even if you test and then release the newly developed code, the integration of the new feature with other dependencies often remains untested or passed on to the next sprint for testing. But it is already broken by then–and the same cycle gets repeated. Let's ship it now and fix it later.

To solve this problem, you need an approach that can:

• Automatically generate integration tests from the application traffic, so that devs don’t have to write/maintain these tests.

• More importantly, these tests automatically update themselves as you push new changes to your application, hence catching all the regressions at the point of origin only.

Introducing changes to a large and cohesive code base can be challenging. When you add new features, fix bugs, or make enhancements, it might affect how the current version of your app, web application, or website functions. 

Although automated tests like unit tests can help, this guide on regression testing offers a more thorough approach to managing these changes. It will walk you through how to ensure that new updates don’t disrupt your existing functionalities, giving you a reliable method to build a regression suite.

What is Regression Testing?

Regression testing is very simple to understand.

Catch all the regressions/changes as and when any of your service undergoes modification. Ask us how?

You might need to carry out regression testing after several types of changes, such as:

• Bug fixes

  
  

• Software enhancements

  
  

• Configuration adjustments

  
  

• Even when replacing hardware components

Why Regression Testing?  

Regression testing is crucial for your development process because it:

• Detects Issues: It helps you spot any defects or bugs introduced by recent changes, making sure that updates don’t mess up existing features or new code.

  
  

• Ensures Stability: It confirms that your current features stay functional and stable after modifications, preventing unexpected behavior that could disrupt your users.

  
  

• Mitigates Risks: It helps in identifying and addressing potential risks from changes, avoiding system failures or performance problems that could affect your business operations.

• Prevents Domino Effect: By catching issues early from minor code changes, regression testing helps you avoid extensive fixes and keeps your core functionalities intact.

• Supports Agile: It fits well with Agile practices by allowing for continuous testing and frequent feedback, so you don't end up with a buildup of broken code before releases.

• Enhances Coverage: Regular regression tests boost your overall test coverage, helping you maintain high software quality over time.

Example of Regression Testing

Catching Regressions in a Banking Application: A Real Case Study

Challenge: When new features were added to the online banking app, there was a risk that they might disrupt existing functionalities.

Approach:

We set-up HyperTest SDK on each of the service and rest everything it can take care of.

• HyperTest automatically started generating integration tests from the application traffic.

• It found some regression in its replay/ test mode, basically deviation/change from the baseline response that it recorded during the record mode.

• It reports that change as a regression and now it's up to you to roll back to the previous version or to update all the dependent services.

In this banking app example:

• our oldBalance was 1000.

• after addition of 500, the newBalance should come as 10500.

• but due to some modification in this service, now the newBalance is coming as 9500.

  
  

Results:

The expected response is the baseline response against which the new/ real response is compared to and regressions like this are reported.

So instead of addition, the updated logic is doing subtraction, which is something to be corrected immediately considering how crucial the operations are in fintech app.

Regression Testing Techniques

When you are adding regression testing to a mature project, you don’t have to test everything from the beginning. Here are some techniques you can use:

• Unit Regression Testing: Start with a broad overview of your code changes. This approach is great for kicking off regression testing in your existing project and involves testing specific items from your list.

  
  

• Partial Regression Testing: This technique divides your project into logical units and focuses on the most critical parts. You have to create specific test cases for these areas while applying unit regression testing to the other modules.

  
  

• Complete Regression Testing: This is the most detailed approach. It involves a thorough review of your entire codebase to test all functionalities that could affect usability. While it’s comprehensive, it’s also time-consuming and is best suited for earlier stages of your project.

  
  

By choosing the right technique, you can effectively manage your regression testing and ensure that your project remains stable and reliable. Now, let us see how to execute regression testing. 

Process of Regression Testing

When you are performing regression testing, here’s a step-by-step guide to follow:

• Change Implementation: Start by modifying your source code to add new features or optimize existing functionality.

  
  

• Initial Failure: Run your program and check for any failures in the test cases that were previously designed. These failures will likely be due to the recent code changes.

  
  

• Debugging: Identify the bugs in your modified source code and work on debugging them.

  
  

• Code Modification: Make the necessary changes to fix the bugs you’ve identified.

  
  

• Test Case Selection: Pick the relevant test cases from your existing suite that cover the modified and affected areas of your code. If needed, add new test cases to ensure comprehensive coverage.

  
  

• Regression Testing: Ultimately, you must perform regression tests with the chosen test cases to verify that your modifications do not cause fresh problems.

By adhering to these procedures, you can guarantee that your software's performance is not harmed by your updates. However, it is important to build a regression test suite that includes different test cases for a specific type of feature of software applications.  Such a regression test suite is executed automatically whenever a code change is made. Let us understand this in detail.

Best Practices for Your Regression Test Suites

When it comes to developing, executing, and maintaining your regression test suites, here are five best practices to keep in mind:

• Think about the specific purpose of your regression test suite. Design it with that goal in mind and manage its scope to ensure it stays focused.

  
  

• Choose your test cases based on factors like code complexity, areas where defects tend to cluster, and the priority of features. This way, you’re targeting the most important areas.

  
  

• Make sure the test cases you select are risk-based, giving you the right coverage for potential issues. This helps you catch problems before they affect your users.

  
  

• Your regression test suite should not be static. Regularly optimize it to adapt to changes in your application and ensure it remains effective.

  
  

• For the test suites you use frequently, consider automating them. This can save you time and effort, allowing you to focus on more complex testing tasks.

Conclusion

Effective software regression testing is crucial for keeping your application running smoothly and performing well. By following best practices to create and manage a regression test suite, your team can make sure that updates do not introduce new bugs. This ultimately leads to happier users and more reliable operations. This guide is here to help you set up a strong regression testing process.

See how HyperTest can help you in catching all the regressions before they move into production: