What is regression testing?

A test case is a thorough document describing how one should determine whether a part of the software is working properly. It outlines the process, the steps, required information, and expected results. Test cases help to ensure that the program runs as expected by giving clear instructions. All the test cases are re-executed to cross-check whether the existing functionality of the application is working fine, and the new changes have not produced any bugs. Take a look at the regression testing cycle:

When can we perform regression testing?

We perform regression testing whenever the production code is changed. It should be taken up:

1. When new functionality comes in.

For example, a mobile application has a login functionality which allows users to login ONLY with email. Now providing a new feature to login with email or mobile number.

2. When there is a change request (that is, changes in existing functionality).

For example, removing the existing “Remember Password” functionality from login screen.

3. When the defect is fixed or when the code is refactored.

For example, assume that login functionality is not working on the webpage, and a tester reports the bug. Once the bug is fixed by developers, the tester tests it to make sure the login functionality is working as per the expected result.

Simultaneously, the tester tests other functionalities like forgot password, login on mobile, login via SSO, which are also working fine (which are related to the login).

4. When there is a performance issue fix.

For example, loading the screen on the application that has training videos takes 7 seconds, reducing the load time to 3 seconds.

5. When there is an environment change.

Usually, five environments are used in SDLC:

• dev instance
• stage instance
• alpha instance
• beta instance
• production instance

Whenever the product code is deployed on the next instance, regression testing assures that the software product performs flawlessly on each environment.

For example, when we release the product, it is important to test the functionality at the production instance as well.

What is continuous regression testing?

Continuous regression testing extends the principles of continuous development and deployment into the regression testing period. It ensures the ongoing validation of the software functionality rather than limiting tests to specific cycles. Regression tests run continuously during development, post development, and both pre and post release. Testing becomes an integral part of every iteration and development phase.

Here are the advantages of continuous deployment:

1. Smaller, more manageable code changes make issue isolation simpler.
2. Speedy defect resolution with quicker feedback loops.
3. Software delivery speed is improved with shorter release cycles.
4. By identifying and fixing defects early, costs are reduced.

By adopting continuous regression testing, DevOps and Agile teams can maintain software quality, accelerate deployment, and improve stability.

Let’s look at the stages of regression testing.

Stages of regression testing

• Compiling test suite: Select effective non-functional and functional test cases that have previously detected bugs.
• Performing regression testing: Execute tests to identify any unintended issues caused by changes.
• Debugging: Developers analyze and fix detected bugs.
• Retesting: Verify bug fixes. The team decides whether to proceed if a fix is too complex for a minor issue.
• Final regression testing: Rerun the test suite to ensure fixes haven’t affected the application’s functionality.

This cycle ensures software quality and stability after every update.

Let’s figure out what your strategy can be, with regards to regression testing.

What should be a Regression Testing Strategy?

Regression testing can be performed manually or can be automated to run daily. Prioritizing the regression test cases depending on critical and frequently used functionalities. In the case of frequent regression testing, it is more effective to automate the test cases.

Regression testing approaches depend on factors like the significance of changes, the frequency of updates, and the potential effects on pre-existing functionalities. To ensure maximum effectiveness, one should make sure that test coverage includes all possible test cases and impacted functionalities. Identify which test scenarios should be automated versus manual tested, while introducing automation. Automation helps optimize resources and time.

Risk analysis is crucial. Evaluating the project’s size, complexity, and business impact to prioritize test cases accordingly is important. Certain high-risk areas must undergo more testing to prevent critical problems.

Manual regression

In manual regression testing, testers execute test cases without the help of automation tools. This approach is particularly effective for assessing new features or changes where automated scripts are not yet available, things that need human judgement, and intricate test cases that are difficult to automate due to complexity or variability. Manual regression testing is the most diligent form of precaution testing you can apply before you move on to the next phase of your product’s journey.

(a) Strategy for performing manual regression

1. Have a defined/prepared functionality checklist in place. Checklists can be multiple depending on webpage/mobile/screen-wise/feature-wise. 

2. Gather all test cases you intend to execute, including but not limited to: 

• All integration test cases
• All complex test cases
• Boundary value test cases
• A sample of successful test cases
• A sample of failure test cases

3. Prioritize the test cases. Selecting test cases based on priority will greatly reduce the regression test suite. 

Automated regression

An automation team progresses on automating test cases on web and mobile applications. Working in agile paradigms, releases, and software revisions are frequent. With this, a rapid regression testing process is required. Using this, product teams can receive more informative feedback and respond instantly. You might need to re-run regression tests. Automated tools allow you to do so quickly and efficiently.

(a) Strategy for performing automated regression

Automating regression means to automate the application of workflows, plans, scripts, and other activities.

1. Outline what can be automated and how.

2. Gather all test cases you intend to execute, including but not limited to:

• All integration test cases
• All complex test cases
• Boundary value test cases
• A sample of successful test cases
• A sample of failure test cases

3. Gauge the time needed for the test cases execution.

4. Focus on improvements that can be made to the test cases.

(b) Business benefits of automating the regression test cases

Automating regression test cases simplifies the testing process, enhancing the accuracy, speed, and scalability. By reducing the manual labor and speeding up the feedback, businesses can have software stability while optimizing costs and efficient resource utilization.

• Faster than manual operations: Automated jobs are often completed in a short period and with superior results compared to manual operations.
• Cost benefit: Use of open source will cost no penny. Also, the time required to complete all the tests can reduce the costly project delays.
• Shorter regression cycles: Manual execution is always on the higher side, however, automating the same gradually decreases the minor maintenance. And automation truly has reduced the resource efforts of executing the regression test cycle by 70-80%.
• Extended test coverage: As per our case study, the automation regression coverage was five times more than the manual regression coverage after 4 weeks of using the automation tool.

While automation increases efficiency, consistency and facilitates frequent testing cycles, manual testing proves to be important for cases that require human intervention and understanding. A balanced strategy that incorporates both methods is necessary for complete regression testing.

Optimize regression testing with our readily available best practices, ensuring your success.

Download Infographic

Why is regression testing important?

Software development is a vast process. Different types of testing ensure that the development goes smoothly, and we’re left with the best outcome.

In software development, regression testing ensures that applications remain stable post modifications and prevent disruptions. As we saw, it verifies that existing functionalities continue to work after code changes and it identifies defects early on. This reduces the time and cost of fixing issues in the later stages of development. There is continuous improvement with each new release resulting in a smooth user experience.

Additionally, modern applications interact with multiple systems. Regression testing warrants updates to work without a hitch within the existing system as well as the external interfaces. With growth comes the risk of compromise. Regression testing makes sure that the new features do not compromise the system performance or the ability to handle the increased loads.

Functionality testing is a type of testing that only inspects the behavior of the new features and functionalities. However, it still needs to confirm their compatibility with the existing ones. Therefore, without regression testing, it is more difficult and time-consuming to investigate the root cause and the architecture of the product.

That’s why developers and testers must not leave even the smallest stone unturned to check for what is NOT supposed to go out.

Additionally, learn more about User Acceptance Testing in our blog.

What is the difference between UAT and Regression testing?

User Acceptance testing, or UAT is not the same as Regression Testing. UAT is a conventional waterfall idea that follows a sequential design process from top to bottom. Here, the entire program is built as a bundle. This is after testing it multiple times and then giving it over to the user. Regression testing takes place in an agile setting in which both developers and users are active participants. Retests are performed on software modifications. This is to ensure that any new changes to the code do not disrupt the operation of previously functional software.

Regression testing guarantees that recent code changes do not have an unfavorable effect on current functionality. User Acceptance Testing (UAT) verifies that the product fulfills business objectives and user expectations.

Regression testing guarantees that recent code changes do not have an unfavorable effect on the current functionality of the software. User Acceptance Testing (UAT) verifies that the product fulfills business objectives and the user’s expectations.

Now let’s delve into the role of GenAI in regression testing.

Integrating Generative AI (GenAI) into regression testing

Integrating Generative AI (GenAI) into regression testing can do wonders for software quality assurance by automating and enhancing the testing processes. Let’s look at how we can do that:

1. Automated Test Case Generation: GenAI can analyze user requirements, codebases, and data to generate comprehensive test cases automatically. This reduces the manual effort and ensures thorough coverage.
2. Predictive Analysis: By examining historical test data and behavior of the application, GenAI can predict defects. This helps teams to proactively address the issues before they manifest.
3. Enhanced Test Data Generation: GenAI models can generate realistic and diverse test data that improves the quality of regression tests.
4. Continuous Testing in CI/CD Pipelines: Integrating GenAI into Continuous Integration/Continuous Deployment (CI/CD) pipelines enables continuous testing. This results in rapid feedback and maintenance of the software stability.
5. Test Suite Optimization: GenAI can help identify obsolete or redundant test cases. This facilitates the efficiency of the test suite.

By incorporating GenAI in regression testing, businesses can achieve improved accuracy, faster release cycles, and higher efficiency. It ultimately enhances software reliability and software quality.

Send us an email at Nitor Infotech with your feedback about this blog. Learn more about our quality engineering services.