What Is Regression Testing and How to Run It?

As soon as developers get ready-tested software pieces, they introduce the required changes. Often, any additions the software system develop new defects. But there’s a solution: regression testing service. It can be a part of manual QA testing services or a part of test automation.

The purpose of regression testing is to catch the accidentally introduced bugs and to ensure that previously eliminated defects aren`t creatable. In such a way, regression testing ensures that code changes don’t impact the existing program features. It has to be performed every time the developers modify a software component or a feature.

Software regression testing increases chances to detect bugs after the introduced changes. It facilitates research of undesirable side effects that resulted after new operating environment implementation. The test also deals with bugs: it finds early-stage and ingrained errors as well as ensures that old bugs won`t harm the system. As a result, testing improves product quality.

The test is required when new software features are introduced. Also, it is necessary to conduct when developers fix bugs or modified product code.

Best Regression Testing Techniques

An effective regression test can be carried out via the following list of techniques:

• Retest All. Here, QA engineers double-check the entire software set. In many cases, such tests are automated because it’s not reasonable to make repetitive tests.
• Test Case Prioritization. The basic objective is to focus on a limited set of test cases. The most successful and useful tests are executed ahead of all less critical check-ups.
• Schedule Maintenance. It’s better to create a schedule for testing. It will become a part of a software development life cycle and always place that process on the front burner.
• A Test Management Tool Usage. The instrument will give the opportunity to track regular tests and record test results in the future.
• Break Down and Classify Tests. Due to the refactoring of the code base itself, it is easier to work with tests, find out and estimate them. After refactoring, tests need to be categorized. Eventually, the classes of smaller checks can be prioritized over others, making the grading and implementation much easier over time.
• Implement Exploratory Testing. The regression checking should have exploratory testing phase, which helps to make sure that tests pass while the software works per users’ expectations.

Regression Testing Process

With the addition of new functionalities, the scope of regression testing will keep increasing. An effective strategy calls for careful planning and prioritization. We’d recommend starting with the following steps.

1. Create a regression test suite the team is going to update as software evolves.
2. Examine the changes & analyze their impact on different components.
3. Determine the areas which are more prone to risks and failures.
4. Create new test cases or change the existing ones when necessary.
5. Prioritize the test cases & estimate the time for their execution.
6. Identify the test cases that can be automated and put it in motion.
7. Keep polishing the test suite by deleting outdated test cases and adding new ones.

Pay attention to the fifth point of a plan. When it comes to prioritization of the test case, it makes sense to arrange them in a way to maximize early fault detection. You can select your test cases based on the following criteria:

• test cases that verify core features of the product;
• test cases of functionalities that have undergone recent changes;
• test cases with frequent defects;
• test cases with functionalities highly visible to users.

Tools for Regression Testing

QA specialists may perform regression testing manually, although it is time-consuming. By contrast, automation tools save 60% of the time to run the test and reduce 40% of money wastes. Here are a few notorious and well-established regression testing tools:

• IBM Rational Functional Tester. This platform is regarded as the best tool for functional and regression testing. It checks software programmed in Java, SAP, Net and has its bespoke peculiarity – Storyboard testing.
• Sahi Pro. The best choice for testing large web applications. Sahi Pro suits for tough-deadline projects. Its automated regression testing platform enables performing tests quickly with minimum maintenance effort.
• Selenium. One of the most effective automated tools for web application testing. With the help of Selenium WebDriver, QA engineers perform powerful browser-based regression tests. The tool operates via cross-environment, OS & browser support. Moreover, it is compatible with different programming languages and testing frameworks. It enables using Selenium for frequent regression tests.
• TestComplete. It is good at executing parallel regression tests, quickly detects code bugs. The platform creates stable tests that are unbreakable under UI changes. TestComplete doesn’t require manual intervention as it runs regression tests automatically.
• TestDrive. A tool for executing easily deployable tests via code free test automation.
• Regression Tester. The desktop tool enables remote regression testing of web-based applications. It helps to re-run the tests multiple time and to create the list of necessary tests easily.
• Quick Test Professional. The data-driven tool is used for automated testing and has a special VBScript language, which was created by Microsoft.

Regression VS Retesting

For many, regression testing often means retesting the existing software features. These testing types require different approaches and set different goals. The purpose of regression testing is to detect the software system side effects resulted from any code modifications. Unlike retesting, regression checks for unexpected defects. By contrast, retesting confirms if the tests cases broken in the final execution work correctly. It deals with the original fault of tests cases. QA engineers do retesting by defect fix, while regression doesn`t deal with the bug verification.

Moreover, regression can be automated and carried out parallel with retesting. Retesting cannot be automated. It executes a defect with different inputs and a new build, although data and environment remain the same. It is always of higher priority in the software strategy plan. However, regression doesn`t cover the whole software; only modified parts undergo testing.

Regression testing is an integral stage of the quality assurance process. An effective regression QA strategy with automation at its core prevents unexpected bug damages and saves the projects from going over budget.

Automated Regression Testing

Regression testing takes place at the end of every iteration, and that makes it a perfect candidate for automation. Since we need to check at least the core functionality after even minor code changes, the regression test suite will be highly repetitive. If a product is dynamic and frequently updated with new features, it means that you have stable functionality to automate and manual regression testing cases to use as the basis.

What are the benefits of automated regression testing?

• It facilitates and accelerates the checks of the core functionality.
• The team gets highly accurate results spending minimum effort on checkups.
• The scripts are highly reusable, so it is easy to maintain the test suite.
• It is an opportunity to reduce the number of routine tasks.
• You get a chance to reduce the product’s time-to-market.

At the start of automated regression testing, QA engineers write autotests on existing test cases covering the main functionality of the software/application. Then, the QA team runs tests within a specific time interval. Also, they conduct the tests each time a new build is created or updated. The final stage includes a full-scale result analysis.

Final Thoughts

In the end, knowledge really is power when it comes to regression testing. By keeping bugs in your sights, they’re less likely to take you by surprise. When a known bug shows up after changes, you’ll have a clue on how to handle it quickly and effectively. Without regression testing, you’ll be left scratching your head, trying to remember what exactly it was that caused this the last time.