Regression Testing: What Is It and How to Do It?

Posted by Anya | January 16, 2021
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9353 Views | 7 Min Read

Regression Testing

The goal of software testing is to find and fix bugs. However, after a bug gets fixed, often other bugs ensue. This is when Regression Testing comes into play. Regression testing ensures that additional problems do not come up after a bug fix or a code change. Hence, every software product company performs Regression Testing.

Regression testing is executed after making changes to a software product and retests the product areas that may have been impacted by the fix. Regression testing can be automated or performed manually by executing a particular set of test cases (test scripts in case of Automation). No matter how the regression test is executed, this type of testing is critical for delivering a high-quality software product.

Why Do We Need Regression Testing?

When software developers fix a bug, add new functionality, or modify an existing feature or functionality, they must change the program code. Even a slight change will likely result in a plethora of new bugs. In such a scenario, a Test Engineer can reveal and pinpoint undesirable side effects through regression testing. A properly executed regression test suite is vital. It is imperative that after a bug fix, the original product does not stop working.

Advantages Of Regression Testing

Some of the other advantages of regression testing are:

  • It dramatically improves the product quality.
  • Manual test cases can be automated, and this automation principle can be applied to regression checks.
  • A successfully executed regression test suite ensures that the bugs are detected early and fixed early.
  • It thoroughly validates that the code modifications do not impact the correct functionality of already tested code – detects every side effect of any code change.
  • Regression tests may be used during the integration testing phase also. In this case, they will be helpful in detecting bugs across different systems when putting two systems together.

How To Execute Regression Testing?

Regression Testing can be executed both manually and in an automated manner. Test Engineers primarily use special techniques that have been classified into four types:

  • Corrective Regression Testing – These tests can be reused, there are no changes in the specification.
  • Progressive Regression Testing – Several new tests are created as the specification is changed.
  • The Retest-All Strategy – This is a time-consuming procedure; all tests are reused. Here we can achieve a higher speed of execution if the tests are correctly automated.
  • The Selective Test Strategy – Only the tests connected with the modified code section are rerun.

Tips For Regression Testing Strategy

If you want to make the most of your regressions test suites, it is essential to plan a proper strategy by keeping certain factors in mind. Here are some ways to help you create a winning regression testing strategy:

  • Execute All Existing Tests Once Again. After the product release, Test Engineers have to check problem areas once again. Many times this can be a challenge, especially when it comes to executing manual testing. Automated testing is recommended here.
  • Run High Priority Tests First. About 50% of time spent on regression testing should be devoted to repeating tests that concern the application’s essential functionality.
  • Check The Complicated Features Next. Many applications have sophisticated and complicated parts, which can cause problems. Although the functionality is difficult to understand/comprehend, the quality of their functionality must be excellent.
  • Execute Exploratory Testing. While learning the software version’s new features, design new tests for them, and execute them. In the course of this testing, many new bugs will be found.
  • Boost productivity and reduce time/efforts spent on running tests with the help of automated testing. Using automation scripts, it is possible to perform tests much quicker and in a more effective way.
  • Finally, it is imperative to perform random testing. A software tester assumes the role of a user and tests randomly. Because there is always some problem or another, it is important to perform random testing.

Regression Testing Example

Here is an example of regression Testing needed for the Tesla website. This company generates billions of dollars in annual revenues from its Website. Hence their websites must always be up and running – functionally, reliably, and with good performance.

Example – Tesla

On the front page of, you can see all the products that Tesla sells.


When Tesla releases their next product, i.e., the Cyber Truck, the developers at Tesla will add a new entry to the Website, most likely next to Model Y. But a lot of care needs to be taken to make sure that even though new UI flows are added to a new “Cyber Truck” entry on the main page, the rest of the product UI flows continue to work functionally the same way as before. A Regression test suite is executed for this purpose. These Regression test cases can be manually executed, or they can be automated using a prevalent Automation test framework called Selenium.

Let’s say one of the Regression tests fail; this means that an existing function of the Website broke while adding a new product flow. This bug needs to be immediately logged and fixed. This Regression test suite should be executed every time a minor or a major UI flow addition/changes are made to the Website. Similarly, the Regression test suite should also be enhanced to cover more UI flows with the help of newer test cases. This ensures that the Website is always up and running; any time there is a breakage, it is immediately detected and flagged with the help of a Regression test suite.

Tools For Performing Successful Regression Testing

Here are some tools that can be useful for creating and executing Regression tests. There are a lot more, but these are some of the best tools. However, the requirements of each product should be thoroughly studied before deciding which ones to use. Here is a comprehensive list:

  • Automated Testing tools
    • Selenium: Framework to test web applications.
    • Appium: Automation tool for running test scripts and testing applications via a webdriver.
  • Test Case Management tools
    • Tricentis: Helps with the automation of software tests.
  • Overall Test Infrastructure, Management and Execution Environment
    • LambdaTest: Here you can perform manual or automated testing across different browsers.
  • Bug Reporting and Task Management
    • Atlassian JIRA for Bug reporting and logging data
    • Asana for Task and Project management

Although Regression Testing may be time consuming and arduous, it is crucial and must be done. You don’t want your product to stop working when you add a small little feature.


In short, Regression Testing is to be executed when

-Any change -big or small is made to code.

Regression testing can be done in many ways, including Corrective regression testing, Progressive regression testing, Retest-All Strategy, and Selective Strategies.

Some tips for strategies pertaining to regression testing include Running High priority tests first, executing exploratory testing, etc.(Please scroll back to the tips section).
Don’t fret if you think Regression Testing is hard; there are always products like LambdaTest, Selenium, and Appium to help you.

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