What is Regression Testing?

When, how, and why you should regression test, plus how to speed up regression testing with AI.

Key Takeaways

  • Regression testing is a crucial part of the software development lifecycle that involves re-executing previously tested features to ensure they still function correctly after changes or modifications have been made to the system.

  • The purpose of regression testing is to ensure software quality, reliability, and compliance by catching any unintended side effects or defects introduced by code changes, updates, or bug fixes.

  • Regression testing helps prevent issues in the production environment, saves time and resources by identifying and fixing bugs early in the development process, and builds user confidence in the software's stability and reliability.

  • Launchable leverages machine learning to intelligently speed up regression testing by predicting the test cases with the highest likelihood of failure, improving software releases.

In the dynamic landscape of software development, new features, updates, and bug fixes are continually being introduced through a series of code releases. However, with every code change comes the unintended risk of impacting other parts of the software once it is deployed.

To mitigate this risk and ensure the stability of the software, quality assurance teams rely on regression testing.

What is Regression Testing?

Regression testing is an essential part of the software development lifecycle that involves re-executing previously tested features to ensure that they still function correctly after changes or modifications have been made to the system. The purpose of regression testing is to ensure the quality, reliability, and compliance of software applications and systems after changes.

Throughout the SDLC changes or modifications to the system are made to fix defects or add new features. These changes may unintentionally introduce new defects or impact the existing functionality of the system. Regression testing helps to catch these issues before they become more serious and costly to fix.

Why Should You Regression Test?

One of the main benefits of regression testing is that it helps to ensure the quality of the software. By catching defects early, regression testing helps to prevent issues from occurring in the production environment, which would negatively impact your user experience. By regression testing, you save time and resources from having to fix missed bugs later on in your development process.

Regression testing helps to build user confidence in the software. By performing regression testing, developers can demonstrate that the software is reliable and defects-free. This helps to build trust and confidence in the product among users, which can lead to increased adoption and usage of the software.

In certain industries, such as healthcare or finance, regression testing is essential for compliance. Any changes or modifications made to the software must stick to compliance guidelines – regression testing helps by checking changes against compliance requirements. 

When do you Regression Test?

Since regression testing verifies that existing functionality isn’t negatively impacted by changes, updates, or bug fixes, it’s often performed after the following actions:

  1. After software updates, patches, or bug fixes to ensure existing features work as expected.

  2. Following code changes to check for regression bugs and unintended side effects.

  3. When new components are integrated to confirm existing functionalities remain intact.

  4. After bug fixes to ensure they didn't introduce new issues.

  5. When configuration changes occur to verify the system still functions correctly.

The timing and frequency of regression testing depends on the level of complexity of your software and changes. It can be integrated into a CI/CD, conducted after each iteration, or performed before major releases. The goal is to catch regression issues early and maintain software stability and reliability.

Related Resource: Seven Types of Regression Testing

What is the Regression Testing Workflow?

Regression testing can be performed manually or automated, depending on the complexity of the application and the resources available for testing. Automated regression testing involves using software tools to execute a predefined set of test cases, while manual regression testing involves manually re-executing a set of test cases. Regardless of the method of regression testing, the regression testing workflow follows these steps:

  1. Detect Source Code Changes: To build a strong regression test, pinpoint the impact and risk of the latest code change. Review code changes using Git to identify modules and components that require testing.

  2. Prioritize Changes and Impacted Areas: Prioritizing testing is essential for QA teams to ensure critical components are thoroughly tested, especially for changes that affect essential features or significantly alter the application's behavior. Prioritization becomes even more critical when dealing with larger codebases, and regression testing is often automated due to its repetitive nature.

  3. Assess Entry Point and Criteria: To determine the starting point for the regression testing of the new codebase, identify the specific components, modules, and functionalities impacted by the code changes. The entry criteria, including code reviews, completed unit testing, and codebase stability must also be decided on before beginning your regression testing.

  4. Identify Exit Criteria: Just as you must determine your entry point, exit criteria must also be determined prior to beginning your regression tests. Define the minimum conditions that must be met to indicate the completion of testing. This includes requirements such as reaching desired test coverage, successful testing of critical functionalities, and meeting performance or stability benchmarks. Determining this exit criteria is critical in determining when you can proceed to the next development stage. 

  5. Schedule Regression Tests and Execute: Determine the optimal timing and sequencing of regression tests based on project timelines and resource availability. With the schedule in place, it's time to execute the regression testing, ensuring that the tests are carried out effectively and in accordance with the established plan.

  6. Rinse and Repeat: The process of regression testing involves re-executing a set of test cases that have already been executed. By re-executing these test cases, developers can determine whether any changes or modifications have impacted the software's functionality. This is why Step 4, identifying your exit criteria is so important – otherwise, how would you know when you’re done?

While automated regression testing is commonly used, there are ways to further enhance its efficiency. For example, one of the greatest bottlenecks to regression testing — and software testing in general — is attempting to run a large number of test cases too frequently. By carefully selecting and prioritizing test cases, teams can speed up regression testing and improve software quality much more efficiently.

Speed Up Regression Testing with Launchable

To ensure comprehensive test coverage, DevOps and quality assurance teams often build extensive regression test suites. However, this can create delays and bottlenecks in the software delivery process. Launchable addresses regression testing congestion by empowering teams with data-driven automated regression test selection.

As a developer-first software testing platform, Launchable leverages machine learning to predict the test cases with the highest likelihood of failure, using code and test metadata. This intelligent approach allows your development team to focus on the most critical areas, resulting in faster and more reliable software releases.

No more guesswork when it comes to important tests. Empower your development teams with more confidence and real-time feedback. Optimize regression testing and streamline your software development lifecycle with Launchable.


Seeking Your Expert Feedback on Our AI-Driven Solution

Quality a focus? Working with nightly, integration or UI tests?
Our AI can help.