Comparison between Regression Testing and Re-Testing

Software TestingAutomation TestingTesting Tools


Re-Testing is the process of checking individual test cases that have been identified as having a defect or bugs in the final execution. In most cases, testers discover these flaws while testing the software program and report them to the developers for correction. The developers then repair the bug(s) and return it to the testers for review. Retesting is the name for this continual procedure.

Example − Assume that Build 1.0 has been released. The Test Team discovered certain issues (for example, Defect Id 1.0.1 and Defect Id 1.0.2) when testing Build 1.0 and reported them. The test team checks for faults 1.0.1 and 1.0.2 in Build 1.1 (only if these two problems are specified in the Build 1.1 Release Note) to see whether they have been addressed.


  • Once a tester discovers an issue, the bug is submitted to the Development Team according to the Bug Life Cycle. The bug's status should be "New."

  • The bug may be accepted or rejected by the Development Team. If the development team agrees to repair the problem, it will be included in the following version. The bug's status will be "Ready For QA."

  • The tester now checks the bug to see whether it has been addressed or not. Retesting is the term for this kind of testing. Retesting is a method of testing that is done on a regular basis. We utilize the same test cases and test data that we used in the previous release.

  • If the problem is not detected, the status of the bug is changed to "Fixed," otherwise the status is changed to "Not Fixed," and a Defect Retesting Document is sent to the development team.

When Should We Re-Test

  • When a specific problem fix is mentioned in the Release Note − Once the development team has released a new version, the test team must test the previously reported problems to ensure that they have been resolved.

  • When a Bug is Turned Down −Occasionally, the development team rejects a few problems identified by testers, citing the bug's status as Not Reproducible. In this instance, the testers must retest the same problem to ensure that it is legitimate and repeatable for the developers.

  • When a client requests a retest −The Client may sometimes request that we repeat the test in order to establish trust in the product's quality. In this situation, the product is retested by the test teams.

    A product should never be launched after modifying the code and just retesting the problem fixes; we must also do Regression Testing.

What is regression testing and how does it work?

Regression Testing is a sort of software testing used to ensure that a recent program or code modification hasn't broken current functionalities. Regression Testing is just a complete or partial re-execution of previously performed test cases to confirm that current functionality is working properly.

Regression testing ensures that new code modifications do not have unintended consequences for current functionality. It guarantees that the old code continues to function after the most recent code modifications have been made.

Regression Testing is Required − The need for regression testing emerges most often when there is a need to alter code and we need to see whether the changed code impacts other parts of the software program. Regression testing is also required when a new feature is introduced to a software program, as well as for bug and performance issues.

Regression Testing: A Step-by-Step Guide

To begin the Regression Testing process, we must first debug the code in order to find any flaws. After the defects have been detected and the necessary modifications have been implemented, regression testing is performed by choosing appropriate test cases from the test suite that cover both updated and impacted code sections.

Enhancements, mistake fixes, optimization, and elimination of existing functionalities are all part of software maintenance. These changes might cause the system to malfunction. As a result, regression testing is required. The following strategies may be used for regression testing:

All of the tests should be repeated.

This is one of the Regression Testing approaches in which all of the tests in an existing test bucket or suite are re-run. This is quite costly since it takes a significant amount of time and money.

Selection of Regression Tests

Regression Test Selection is a method in which a subset of test cases from a test suite is run to see whether the updated code has any impact on the software application. Test cases are divided into two categories: reusable test cases that may be reused in subsequent regression cycles and outdated test cases that cannot be reused.

Test Case Prioritization

Prioritize the test cases based on their business effect, criticality, and frequency of usage. The regression test suite will be considerably reduced if test cases are prioritized.

Regression Testing Test Cases Selection

According to industry statistics, a large proportion of defects reported by customers were caused by last-minute bug patches that had unintended consequences, making picking the Test Case for regression testing an art and not a simple task. The following test scenarios may be used to create effective regression tests −

  • Test scenarios with a high number of flaws

  • Users will be able to see more features if they are more visible.

  • Test scenarios that test the product's fundamental characteristics

  • Case studies of functionalities that have experienced significant and recent alterations

  • All Test Cases for Integration

  • All Extensive Test Cases

  • Cases of boundary value tests

  • A number of successful test examples are shown below.

  • A selection of failure test scenarios

Tools for Regression Testing

Regression testing expenses will rise if your software is often updated. Manual execution of test cases increases test execution time and expenses in such circumstances. In such instances, automation of regression test cases is the best option. The amount of automation is determined by the number of test cases that may be reused in subsequent regression cycles.

The following are the most essential tools used in software engineering for both functional and regression testing −

  • Avo Assure

  • Eggplant

  • Selenium

  • Quick Test Professional (QTP)

  • Rational Functional Tester (RFT)

Configuration Management and Regression Testing

In Agile environments, where code is constantly updated, configuration management during regression testing becomes critical. To ensure that regression tests are successful, keep the following in mind −

  • Regression testing code should be run using a configuration management solution.

  • During the regression test phase, no modifications to the code must be permitted. Developer changes must not affect regression test code.

  • It is necessary to segregate the database used for regression testing. There must be no database updates permitted.

A good regression approach saves time and money for businesses. According to one case study in the banking industry, regression saves up to 60% time and 40% money in issue repairs (which would have been discovered by regression testing).

QA candidates often ask about re-testing vs. regression testing.

Regression Testing vs. Retesting

  • Passed test cases are subjected to regression testing, whilst failed test cases are subjected to retesting.

  • Regression testing looks for unintended consequences, whereas retesting ensures that the initial flaw has been fixed.

  • Defect verification is not included in regression testing, but it is included in re-testing.

  • Regression testing is referred to as generic testing, while Re-testing is referred to as planned testing.

  • Automation allows for regression testing, but it does not allow for retesting.

A full comparison with an example is provided below.

Regression TestingRetesting
Regression testing is used to make sure that a recent program or code modification hasn't broken any existing functionalities.After the faults are addressed, retesting is done to ensure that the test cases that failed in the final execution pass.
The goal of regression testing is to ensure that new code modifications do not affect current functionality.On the basis of the defect repairs, re-testing is carried out.
Regression Testing does not include defect verification.Re-testing includes defect checking.
Regression Testing and Re-testing may be done simultaneously depending on the project and resources available.Re-testing has a greater priority than regression testing, thus it is completed before regression testing.
Regression testing may be automated, but manual testing can be costly and time-consuming.The test cases for Retesting cannot be automated.
Regression testing is a kind of testing that is used for a variety of purposes.Re-testing is a method of testing that is done on a regular basis.
Passed test cases are subjected to regression testing.Only failed test cases are subjected to retesting.
Regression testing looks for unintended consequences.Re-testing ensures that the initial problem has been resolved.
Regression testing is only performed when an existing project is modified or modifications are required.With a fresh build, re-testing runs a defect with the same data and environment but different inputs.
Regression testing test cases may be found in the functional specification, user training and manuals, and defect reports for fixed issues.Before beginning testing, test cases for retesting cannot be acquired
Published on 30-Nov-2021 05:25:35