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regression testing

What is regression testing?

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Regression testing is a technique that uses a black box to test. When a code modification in the software is authenticated, it ensures that the change does not influence the product's existing functionality.

regression testing cycle

Testers perform regression testing to ensure that the product continues to function properly after adding new functionality, bug fix, or making changes to an existing feature.

Software testing is a technique used to ensure that any change or update to a piece of software does not impair the software's general functionality.

Software regression testing is a subset of functional tests that are performed on software. To ensure that the old functionality of the program is still operational and that the new changes have not introduced any issues, test cases are re-run.

When there has been a significant change in the functionality of the original version, full regression testing can be performed on the new build. It ensures that the code continues to function properly even as the modifications are being implemented.

Regression testing refers to the process of retesting the elements of the program that have not changed.

The regression testing process is sometimes referred to as the Verification Method in some circles.

The majority of test cases are automated. Test execution can be carried out many times, and re-running the same test cases over and over again manually is both time-consuming and tedious.

When Is The Right Time to Use Regression Testing?

Software regression testing should be performed as soon as possible after the development of a new feature, the improvement of an existing feature, or the implementation of any user interface (UI) changes.

To guarantee that the changes do not harm the software's existing functionality, functional and regression testing should be carried out.

Additionally, whether a small or significant modification has been made to an application, the regression testing procedure should be carried out to ensure that any changes to the program's old functionality are not affected.

Functional regression testing teams must ensure that new code does not clash with existing code, and that code that has not been altered continues to function as planned.

Accordingly, using this type of visual regression testing, it is ensured that the previous functionality of the program continues to function properly and that any recent updates have not introduced any new issues into the application.

As a result, the regression testing method is considered to be a critical component of software quality assurance.

Software regression testing, when performed in conjunction with unit regression testing and integration test cases, aids in the early detection of flaws and the reduction of the cost of resolving and fixing problems.

This practice of software regression testing instills trust in the user that an application is ready to be deployed.

Regression testing is crucial because it ensures that successful test cases code modifications do not re-introduce previously discovered faults, which helps to enhance the overall quality of the software.

Businesses must rely on regression testing services to ensure and deliver high-quality software, and this is an unavoidable cost.

Who Needs Regression Testing?


In the real world, it's difficult to think of a product that never has to be updated. New features, back-end changes, and adapting to handle additional traffic are all things that developers must do to keep their projects relevant and attract new consumers.

It's impossible to keep a software product running smoothly if you don't perform regular regression testing on it.

The following are the significance of regression testing for developers:

Ensure a bug-free performance after changing the back-end code. Adding a new feature can have a significant influence on the overall system, and that impact is not always positive. When a minor piece of code is changed, testers run regression tests to make sure that the system's performance isn't affected.

Add a new feature to the program and see how it performs.

As a result of regression testing, developers may ensure that new features are compatible with existing ones, that the product's architecture can handle more complicated activities without crashing, and so on.

Get to the bottom of the problem and fix it

You should still execute regression testing even if you haven't made any significant modifications to the code. Developers can save time by rerunning the existing test cases rather than writing new ones.

Identify the sections of an application that are most likely to go wrong

Regression testing will aid the software development team in determining which areas of the system are most susceptible to modification and hence have the greatest risk of crashing when implemented. In the future, testers will know to pay more attention to these features' upkeep.

Types of Regression Testing

The regression testing process is not a one-size-fits-all procedure. There are many types of regression testing. It's not just about the size of the test suite when it comes to regression testing, but there are also more methods. Among the most common techniques employed by software regression testing users are the following:

Regression testing process for error correction

Use the regression testing strategy when the program hasn't been considerably changed. Developers rarely construct new regression test cases for these sessions, preferring instead to reuse the old ones.

Testing using a stepwise approach

Using this method, a new component can be tested for its effect on the overall system. Team members must be informed of the exact number and kind of code changes to use progressive regression testing.

New automating regression test cases are created specifically for this type of testing.

Regression testing with a focus on only a subset of possible outcomes

To expedite the testing process, a tester will select a variety of test cases. It's difficult for developers to specify the criteria between the experiment and the range of covered program pieces, even though this method is an excellent way to save money and work on retesting.

Complete regression testing

The regression testing strategy is typically employed when the software development team is unable to accurately quantify the scope of the adjustments or their overall impact. Regression testing provides a complete picture of a system to a QA expert. Finally, before the release of a new build, this is often deployed.

Regression testing tools

Here is the list of the Best Regression testing tools:



With Scriptworks, hands-on manual testers can use their domain experience to develop scalable and repeatable automated test packs that can meet the needs of today's ever-changing environment.

The browser-based UI of Scriptworks provides platform freedom and ease of use. You can run Scriptworks generated test code on any platform, including your desktop, your Continuous Integration (CI) infrastructure, or even in the cloud.

An established technology for producing visual programs led to the development of Scriptworks' intuitive drag and drop visual interface. As simple tests may be developed in minutes, even the most complicated scenarios can be covered with simplicity thanks to the versatility of constructs.

Automated code is always visible in Scriptworks because it is generated directly from the visual design. Build meaningful tests while learning Selenium and coding structures, with the option to add your own custom code if needed.

The Katalon Studio

When it comes to functional testing, Katalon Studio is an end-to-end automation solution that makes these procedures simple tasks for the rational functional tester.

Using Katalon Studio functional testing, you can test your website, web services, and mobile applications all at once. Test scripts can be run on a variety of devices, browsers, and operating systems.

Test results can be seen and forwarded as email attachments in LOG, HTML, CSV, and PDF formats, all of which are extensive and configurable.


Selenium is one of the best regression testing tools for automating web-based applications. For browser-based regression testing and cross-platform regression testing, it's still one of the best tools out there.

Automation of data-driven tests is supported by Selenium's automated test scripts. Large-scale quality assurance teams with advanced testers can benefit from this. Small and midsize teams, on the other hand, will find it difficult to master because of the software's steep learning curve.

Apache JMeter

Automated testing tool Apache JMeter is used to load functional test behaviors and measure the performance of the tests run.

For example, it can run load and performance tests on a wide range of various apps, servers, and protocols while also providing end-users with a comprehensive set of regression tests.

Avo Assure

Avo Assure is a 100% no-code and heterogeneous test automation solution that simplifies and speeds up regression testing.

Cross-platform compatibility lets you test across the web, mobile, desktop, and Mainframe ERPs, as well as accompanying emulators.

Using Avo Assure, you don't have to write a single line of code to perform end-to-end regression testing and ensure fast and high-quality delivery.


Watir, or Web Application Testing in Ruby, is a Ruby-based open-source library.

With a lightweight and flexible user interface, it helps you write tests that are easy to understand and maintain.

It's possible to click links, fill out forms, and validate text using several browsers using Watir when testing a website.

Regression Testing Techniques

Here are the various regression testing technique

  • Retest all
  • Regression Test Selection
  • Test case Prioritization
  • Hybrid
Regression testing techniques

Retest All

Retest all are used to test all the test cases. Re-running all the test cases in a regression testing suite to ensure that there are no bugs caused by changes in the source code is the primary goal of this testing.

When compared to other methods, this one is more expensive because it involves more time and money.

Regression Test Selection

The test cases that are selected for re-execution are taken from the test suite. However, nothing in the suite has been redone. Code changes in the module are taken into account when selecting test cases.

There are two types of test cases: those that can be reused and obsolete test cases. Future regression cycles can use the reusable test cases, but they cannot use the obsolete ones.

Test Case Prioritization

Priority test cases are executed first, rather than those with lower priority. Test cases are prioritized based on their impact on the product and the functionality of the product that is used the most frequently, as well as on their importance.


Regression Test Selection and Test Case Prioritization are combined in the hybrid technique. Select only the test cases that are re-run based on their priority, rather than the whole test suite.

What's the difference between regression testing and re-testing?

It can be difficult for automation novices to distinguish between re-testing and regression testing. There is a superficial resemblance between the two, yet they are very different entities.


For a specific reason, re-testing is a form of testing. Any time a bug in the source code needs to be addressed or a specific test case fails in the final execution and needs to be rerun, re-testing is required.

If new defects have been introduced by updates or changes, regression testing is carried out to figure them out. This step would help to guarantee that all of the software was compatible with one another.

Regression tests

Before regression testing, re-testing is done in a normal development workflow. Only the failed test cases are the subject of re-testing, whereas regression testing examines the ones that passed to look for any unexpectedly new flaws.

Re-testing, as opposed to regression testing, incorporates error verifications.

Regression testing relies heavily on automation, which lets you make the most of your test cases. Adding to this, regression testing eliminates all underlying side effects generated by code modifications in the cheapest and most efficient method feasible.

As you may be aware, incremental and iterative processes are the foundation of the agile methodology. Sprints are short iterations in the development of software or a product.

Each iteration of the code indicates a new feature or addition, which is why there are multiple sprints in a project. Regression testing has a purpose in this scenario.

Regression testing process

Regression testing is made easier by developing a plan early on and sticking to it until the product is ready. The good news is that developing a testing framework is rather simple.

To begin, most QA specialists use the following process to perform regression testing

Step 1. Executing test cases

As part of the process of creating a regression test plan, a QA specialist must gather all of the test cases they intend to run. Using the following guidelines, you may make informed decisions about which tests to take:

  1. Cases should be included in error-prone regions of the program since they are more susceptible to system changes.
  2. Include scenarios that test the product's primary features. The homepage, login page, payment gateway, and so forth are all included in this category.
  3. Include more complicated scenarios, such as GUI event sequences.

Step 2. Estimate the amount of time it will take to run each test case.

Make sure to factor in the amount of time it will take to test each feature. In addition to a session, your testers may need some time to familiarize themselves with the range of tools used for performing regression testing and report on specific tests and add it to the schedule.

This should be considered. Some more elements that could affect the estimated testing time:

  • Creation of test data;
  • Regression test planning (particularly for a new QA specialist);
  • Reviewing test cases.

Step 3. Outline which tests can be automated

It is faster and more accurate to do automated testing than to conduct manual ones. Such scripts can be reused for future projects, which increases software maintenance efficiency and establishes a set of standards for the testing team.

The majority of regression testing scenarios are automated by developers. Nevertheless, a manual check is preferable when dealing with a convoluted chain of events.

Manual testing is typically the only option in cases involving graphical user interfaces.

The best method to minimize misunderstandings among the testing team and maintain the order of the reports is to segregate the manual tests from the automated tests.

Step 4. Prioritize test cases

Identifying and executing the most critical use cases for the program should always be the primary priority of a tester.

Prioritizing is essential for successful session management. To evaluate the usefulness of test cases, you can use the following simple framework.

Priority 0

Sanity tests fall under this umbrella. A QA specialist should focus on testing the product's basic functionality and pre-system acceptability initially, as they provide the most value to both users and engineers.

Priority 1

Some features are critical but not central to your program's functionality, and they come under Priority 1 and should be tested as soon as all of the scenarios labeled with Priority 0 are completed.

Priority 2

Contains test cases that don't add much value to the project, but are essential for avoiding technical debt and developer headaches. There isn't much of a difference for the average user.

Step 5: Use testing tools to speed up the process of testing

Regression testing has a wide variety of tools to help QA personnel plan, prepare, and report. To speed up the process, the team can use these off-the-shelf technologies and follow the best practices of regression testing.

To increase the effectiveness of testing, developers may choose to use the following tools:

  • Selenium is a lightweight web application testing framework.
  • Regression testing for environments and software is provided by QTP.
  • Scriptworks is developed for scalable and repeatable automated test packs that can meet the needs of today's ever-changing environment.
  • Automated testing for Ruby-based apps is made possible with Watir.
  • Human-like actions are precisely replicated by Rational Functional Tester, an automated technology.

Regression testing example

Below are examples of regression testing.

Regression of a bug

Here, issues that are claimed to have been resolved are expressly retested.

Old fix method

Here, previously resolved issues and bugs are retested to ensure that those regions stay intact. This was the genesis of regression.

Method of conversion or porting

In this case, the program is ported to a new platform. This type of regression test is then used to determine whether the transferred program was integrated effectively. The changes will mostly affect the modern environment, rather than the previous one.

Configuration method

The software is run on or in conjunction with a later version of the application or device in use. This is a very similar example to conversion testing.

Nonetheless, the original code and platform remain unchanged; only the environment and a few components coupled with the aforementioned program are altered.

General Functional testing method

A Retest is a larger-scale examination. This encompasses all areas, including those that were previously operational. They examine them to determine whether any of the more recent adjustments harmed their encoding. This is the genesis of automated regression testing.

Build Verification

This example is as much a part of regression testing as it is of any software testing life cycle. This method does not require a large number of relevant test cases or a cumbersome suit to pass a new build.

Typically, the build is physically inspected for any damaged or faulty sections to see whether it is even worth testing in the first place, or if any of the updated components of the new build do not integrate as intended.

When a build fails the smoke test, it is typically rejected in its entirety and not returned with error reports for correction.

Localization method

This example requires tinkering with the program to demonstrate its software connection in a foreign language and in accordance with an alien set of traditional rules.

This will almost certainly require a large number of tests, both old and new, though the majority of the old tests will have been modified to create a more suitable environment for the new language.

In its natural state, regression testing reveals more than just fundamental issues. Additionally, it may be integrated with any other testing technique, since every test can be utilized multiple times. As a result, any test is a regression test.

Regression test suite

The regression testing suite is the set of test cases that are designed to ensure that the software is accurate and correct after fixes or changes are made to it.

There should be a separate regression test suite for each tests levels (i.e., unit testing, system testing, and acceptance testing).

There are white-box tests for entire regression test suite testing and black-box tests for system and acceptance testing, for example. White box tests are used to test the code as it was originally written, while black-box tests are used to test the changed code.

There are two ways to run regression test suites: either manually or through automation. When deciding whether to automate a test, take into account how frequently it will be run. Automated testing costs around 10 times as much as manual testing.

Manual tests are more expensive since they have to be run again and again and again, and each time they have to be done in the exact same sequence of entries.

Once it has been executed, an automated test plays back the recorded or programmed keystrokes. Each subsequent run of the automated test will cost little, especially if it is conducted unattended.

It's a good idea to construct some simple test cases that test the most commonly used functionalities, using a typical task order, to ensure that the system works properly.

Automation is a viable option for these tests, which can be run regularly to ensure that no new bugs have been introduced. However, it will take some time to incorporate the changes to the software into the automated test script.

When a change in the software necessitates testing of a single isolated area, it is more cost-effective to employ a manual technique.

Automation Regression Testing

Automation regression testing solutions allow testers to speed up the time-consuming and resource-intensive task of retesting the complete system each time a new feature or remedy is installed.

There will be minimal or no human intervention in the execution of a succession of pre-written scripts following a code modification.

What Are the Benefits of Automated Regression Testing?

For a product with a large regression test suite that is currently being developed, automated regression testing is recommended. There is just a handful of testing that requires repetition.

Regression testing can be performed in two ways: either completely before each release or partially after each change is made to the code.

In certain situations, it makes sense to automate regression test cases. The amount of test cases that can be reused for successive regression cycles determines the degree of automation.

Challenges Encountered on Regression Testing

The following issues may still arise if your company decides to implement test automation:

Selecting the Right Tool

Without the proper technology, automated regression testing quickly devolves into a time-consuming task with little to show for it.

Skilled Resources

Choosing an automation testing solution that requires a specific set of abilities from the testers means you'll either have to find new talent or invest time and money in training the individuals you already have. Investing is the colloquial term for both.

Choosing the Right Methodology for Testing

You can't just start automating tests if you have the right tools and resources. Before you begin automating tests, you'll need to develop a strategy. A framework may be necessary, or you may choose to employ a tool that eliminates the need for one.

The upfront cost of the investment is rather high

There are further expenditures to consider after hiring and training resources and selecting a test automation tool. Like a building's framework.

Creating test cases and automating tests are two activities that take a significant amount of time and should be included in your budget for test automation. It is, therefore, necessary to calculate the revenue.

To ensure that your investment in test automation yields a return, you must first consider all regression testing costs and then select a tool.

When you buy an easy-to-use solution that doesn't require you to invest in infrastructure, you get two benefits. In addition, if it makes the process of creating test cases simpler and easier, you'll save money and see a faster return on your investment.

Automation Testing: What Can You Do To Make This Possible at a Low Cost?

Automated test cases must adhere to a set of rules and principles known as a test automation framework. There must be a system in place for the greatest possible results from test automation.

Many factors must be taken into account when automating regression testing of an application's user interface (UI).

Automating programs that are expected to be in use for a lengthy period is preferable since it provides a long-term return on the investment.

There should be no difficulty in executing and maintaining automated test cases, as well as proper and timely reporting of errors.

Only those parts that are not expected to change frequently should be automated.

Investing in low-quality automated software testing is a waste of time and resources.

To catch critical defects before they reach the client, test cases should be conducted on all supported devices and screen resolutions.

The automated testing tools you choose should help you save money in the long run. Keep in mind that automation involves several expenses, including but not limited to hiring, training, infrastructure costs, and employee time.

Regression Testing in Agile

The regression suite should be prepared in the early stages of the product development cycle and should be followed until the final deployment of the product. Regression testing can be done in two ways in agile methodology:

Sprint Level Regression

This sort of regression is used to assess the impact of any new features or enhancements rolled out in the most recent sprint. For this purpose, you should select the test cases in accordance with the new feature that has been added to your product.

End-to-End Regression

To confirm that the product's core features work as expected, you must re-run all of the previously completed test cases.

As a result of the short sprints required by the agile methodology, regression testing must be performed regularly.

QA professionals will have a difficult time if you do this manually. As a result, regression testing in an agile way is assisted by automation instead. It aids in the reduction of test execution time and the detection of common errors.

Conclusion Regression testing

To improve the overall quality and user experience, regression testing is essential. If you use regression testing correctly, you can find and fix most of the bugs that have come to light early in the development process.

Additional advantages include technical and business advantages that can be gained by using regression testing in an Agile development environment. You'll have a better budget, process, and error mitigation control over your product if you put in more time and money into preparing and running regression tests.

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Article written by Duncan Brigginshaw
Co-Founder and Technical Director

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