Javatpoint Logo
Javatpoint Logo

What is regression testing?

Regression testing is a black box testing techniques. It is used to authenticate a code change in the software does not impact the existing functionality of the product. Regression testing is making sure that the product works fine with new functionality, bug fixes, or any change in the existing feature.

Regression testing is a type of software testing. Test cases are re-executed to check the previous functionality of the application is working fine, and the new changes have not produced any bugs.

Regression testing can be performed on a new build when there is a significant change in the original functionality. It ensures that the code still works even when the changes are occurring. Regression means Re-test those parts of the application, which are unchanged.

Regression tests are also known as the Verification Method. Test cases are often automated. Test cases are required to execute many times and running the same test case again and again manually, is time-consuming and tedious too.


Here we are going to take a case to define the regression testing efficiently:

Consider a product Y, in which one of the functionality is to trigger confirmation, acceptance, and dispatched emails. It also needs to be tested to ensure that the change in the code not affected them. Regressing testing does not depend on any programming language like Java, C++, C#, etc. This method is used to test the product for modifications or any updates done. It ensures that any change in a product does not affect the existing module of the product. Verify that the bugs fixed and the newly added features not created any problem in the previous working version of the Software.

When can we perform Regression Testing?

We do regression testing whenever the production code is modified.

We can perform regression testing in the following scenario, these are:

1. When new functionality added to the application.


A website has a login functionality which allows users to log in only with Email. Now providing a new feature to do login using Facebook.

2. When there is a Change Requirement.


Remember password removed from the login page which is applicable previously.

3. When the defect fixed


Assume login button is not working in a login page and a tester reports a bug stating that the login button is broken. Once the bug fixed by developers, tester tests it to make sure Login Button is working as per the expected result. Simultaneously, tester tests other functionality which is related to the login button.

4. When there is a performance issue fix


Loading of a home page takes 5 seconds, reducing the load time to 2 seconds.

5. When there is an environment change


When we update the database from MySql to Oracle.

How to perform Regression Testing?

The need for regression testing comes when software maintenance includes enhancements, error corrections, optimization, and deletion of existing features. These modifications may affect system functionality. Regression Testing becomes necessary in this case.

Regression testing can be performed using the following techniques:

regression testing

1. Re-test All:

Re-Test is one of the approaches to do regression testing. In this approach, all the test case suits should be re-executed. Here we can define re-test as when a test fails, and we determine the cause of the failure is a software fault. The fault is reported, we can expect a new version of the software in which defect fixed. In this case, we will need to execute the test again to confirm that the fault fixed. This is known as re-testing. Some will refer to this as confirmation testing.

The re-test is very expensive, as it requires enormous time and resources.

2. Regression test Selection:

  • In this technique, a selected test-case suit will execute rather than an entire test-case suit.
  • The selected test case suits divided in two cases
    1. Reusable Test cases.
    2. Obsolete Test cases.
  • Reusable test cases can use in succeeding regression cycle.
  • Obsolete test cases can't use in succeeding regression cycle.

3. Prioritization of test cases:

Prioritize the test case depending on business impact, critical and frequently functionality used. Selection of test cases will reduce the regression test suite.

How to select test cases for regression testing?

It was found from industry inspection. The several defects reported by the customer were due to last-minute bug fixes. These creating side effects and hence selecting the Test Case for regression testing is an art, not an easy task.

Regression test can be done by:

  • A test case which has frequent defects
  • Functionalities which are more visible to users.
  • Test cases verify the core features of the product.
  • All integration test cases
  • All complex test cases
  • Boundary value test cases
  • A sample of successful test cases
  • Failure of test cases

What are the Regression Testing tools?

If Software undergoes frequent changes, regression testing costs also increase. In those cases, manual execution of test cases increases test execution time as well as costs. In that case, automation testing is the best choice. The duration of automation depends on the number of test cases that remain reusable for successive regression cycles.

Following are the essential tools used for regression testing:

1. Selenium

Selenium is an open-source tool. This tool used for automated testing of a web application. For browser-based regression testing, selenium used. Selenium used for UI level regression test For web-based application.

2. Ranorex Studio

All in one regression test automation for desktop, web, and mobile apps with built-in Selenium Web Driver. Ranorex Studio includes full IDE plus tools for codeless automation.

3. Quick Test Professional (QTP)

QTP is an automated testing tool used for Regression and Functional Testing. It is a Data-Driven, keyword-based tool. It used VBScript language for automation.

4. Rational Functional Tester (RTF)

Rational functional tester is a Java tool used to automate the test cases of software applications. RTF used for automating regression test cases, and it also integrates with the rational functional tester.

What are the Regression Testing and Configuration Management?

Configuration Management in the regression testing becomes imperative in Agile Environments, where a code is continuously modified. To ensure a valid regression test, we must follow the steps:

  • Changes are not allowed in the code during the regression testing phase.
  • A regression test case must be unaffected developer changes.
  • The database used for regression testing must be isolated; changes are not allowed in the database.

What are the differences between Retesting and Regression Testing?

Re-testing Testing means testing the functionality or bug again to ensure the code fixed. If not set, defects need not be re-opened. If fixed, the defect closed.

Re-testing is a type of testing which performed to check the test-cases that were unsuccessful in the final execution are successfully pass after the defects repaired.

Regression Testing means testing the software application when it undergoes a code change to ensure that new code has not affected other parts of the Software.

Regression testing is a type of testing executed to check whether a code has not changed the existing functionality of the application.

Differences between the re-testing and Regression Testing are

Sr. No. Re-testing Regression Testing
1. Re-testing is performed to ensure that the test cases that failed in the final execution are passing after the defects fixed. Regression Testing is done to confirm whether the code change has not affected the existing features.
2. Re-Testing works on defect fixes. The purpose of regression testing is to ensure that the code changes adversely not affect the existing functionality.
3. Defect verification is the part of the Retesting. Regression testing does not include defect verification.
4. The priority of Retesting is higher than Regression Testing, so it is done before the Regression Testing. Based on the project type and availability of resources, regression testing can be parallel to Retesting.
5. Re-Test is a planned Testing. Regression testing is a generic Testing.
6. We cannot automate the test-cases for Retesting. We can do automation for regression testing; manual testing could be expensive and time-consuming.
7. Re-testing is for failed test-cases. Regression testing is for passed Test-cases.
8. Re-testing make sure that the original fault is corrected. Regression testing checks for unexpected side effect.
9. Retesting executes defects with the same data and the same environment with different input with a new build. Regression testing is when there is a modification or changes becomes mandatory in an existing project.
10. Re-testing cannot do before start testing. Regression testing can obtained test cases from the functional specification, user tutorials and manuals, and defects reports in regards to the corrected problem.

What are the challenges faced in Regression Testing?

Regression Testing is a vital part of the QA process; several challenges come.

  • Time Consuming:
    Regression Testing consumes a lot of time to complete. Regression testing involves existing tests again, so testers are not excited to re-run the test.
  • Complex:
    Regression Testing is complex as well when there is a need to update any product; lists of the test is also increasing.
  • Communicating business rule:
    Regression Testing ensures the existing product features are still in working order. Communication about regression testing with a non-technical leader can be a difficult task. The executive wants to see the product move forward and making a considerable time investment in regression testing to ensure existing functionality working can be hard.

What is the importance of Regression Testing?

With the increment of Agile Development methodology Regression Testing has taken on added importance. Many companies today adopt an iterative Agile approach to software development. Many Software as service providers will regularly update their feature or add new functionality to their offerings with each software update. To ensure their core product remains unaffected by new feature additions, those companies will perform Regression Testing.

What are the types of Regression Testing?

Different types of Regression Testing are:

regression testing

1.) Unit Regression

Unit Regression did during the Unit Testing phase, and code tested in isolation; all the dependencies on the unit to tested blocked so that the unit can test individually.

2.) Partial Regression

Partial Regression is used to verify that the code works well even if changes are in the code, and the unit integrated with the unchanged code.

3.) Complete Regression

Complete Regression is on the modules. When change applied on several modules, and also if the change impact on any module is uncertain.

What are the advantages of Regression Testing?

Advantages of Regression Testing are:

  • Regression Testing increases the product's quality.
  • It ensures that any bug fix or changes do not impact the existing functionality of the product.
  • Automation tools can be used for regression testing.
  • It makes sure the issues fixed do not occur again.

What are the disadvantages of Regression Testing?

There are several advantages of Regression Testing though there are disadvantages as well.

  • Regression Testing should be done for small changes in the code because even a slight change in the code can create issues in the existing functionality.
  • If in case automation is not used in the project for testing, it will time consuming and tedious task to execute the test again and again.


Regression Testing is one of the essential aspects as it helps to deliver a quality product which saves organizations time and money. It helps to provide a quality product by making sure that any change in the code does not affect the existing functionality.

For automating the regression test cases, there are several automation tools available. A tool should have the ability to update the test suite as the regression test suit needs to be updated frequently.

Next TopicFunctional Testing

Help Others, Please Share

facebook twitter pinterest

Learn Latest Tutorials


Trending Technologies

B.Tech / MCA