As you must be aware, depending on the stage of development, various types of testing are undertaken during the multiple phases of the software development life cycle (SDLC). Each level of the SDLC has its own set of requirements and objectives for testing to meet.

While many testing methods exist, retesting and regression testing often cause confusion due to their similar names. This article aims to clarify the key differences between these two practices, using clear and professional language. We’ll explore what makes them distinct and their unique roles in ensuring software

Are retesting and regression testing similar? If not, what are the crucial differences between them? This article will provide a detailed comparison to address these questions and eliminate any confusion between Regression Testing vs Retesting.

Retesting vs Regression Testing: Definition, Process, Types, & Advantages

Let’s compare retesting and regression testing with all the aspects like the process of testing, types, advantages and tool.

What Is Regression Testing?

Type of software testing used to ensure that a recent program or code change has not negatively impacted existing features. Regression testing is simply a full or partial selection of previously executed test cases that are re-executed to ensure that existing functionalities continue to function correctly.

This testing ensures that new code changes will not impact existing functionalities. Instead, it ensures that the old code continues to function after the most recent code changes have been made.

Know more: Regression Testing: Complete Guide

Requirement For Regression Testing 

Regression testing is required primarily when there is a need to change the code or there is a need to test whether the modified code affects the other parts of the software application or not. Furthermore, regression testing is required when a new feature is added to a software application and the resolution of defects and performance issues.

When is it Necessary to Conduct Regression Testing?

Testers perform Regression testing in any of the following situations: 

• When a client submits a change request (CR), the code base undergoes alteration.
• In cases, where the testing environment undergoes a change.
• When you move the back-end code to a new platform.
• During the testing process, the developer discovers a critical bug and rectifies it.
• An existing software gets a new feature.
• The developers have addressed the essential concerns about performance difficulties and crashes.
• Fixes have been added to the patch.
• For a better user experience, the application’s UI underwent modifications. 

How To Do Regression Testing?

We must debug the code to find bugs in order to perform regression testing. When bugs are discovered, changes must be made to correct them. 

The regression test is carried out by selecting appropriate test cases from the test suite that cover changes to and affect the code sections. 

In addition, app maintenance entails improving, correcting bugs, optimizing, and removing existing functionality. This adjustment will cause the machine to malfunction. As a result, regression testing is required.

What Are Different Types Of Regression Tests? 

#01 Functional Testing

Entails putting an application’s current version functionality to the test. The most common is a web browser-based functional test that verifies how users interact with the application.

#02 Manual Testing

We write test scripts and perform manual testing using our skills and knowledge in this manual method. 

This is the most widely used type of automated testing. We develop a set of test scenarios based on the requirement test suite. The scenarios are then recorded in a file called a test plan.

#03 Load/Stress Tests

Evaluate the application’s performance under high load conditions. Unit regression testing: verifies individual units within an application.

Integration tests: These tests validate the interactions of an application’s various components.

#04 Planned Testing

Planned testing is a method of testing software development in which you plan out the steps and order in which they will be taken. 

This allows you to keep track of everything that needs to happen so that when something goes wrong, you can figure out what went wrong quickly. It also assists you in determining how long everything will take and whether or not there will be any bottlenecks.

Why Perform Regression Testing?

The process of ensuring that a new version of the software does not introduce any bugs through regression testing. 

After each release or significant change, it is performed to ensure that the modifications introduce no bugs. The goal is to ensure that the code functions as expected without introducing errors or glitches.

The regression testing process is divided into two stages: initial testing and final testing. Before going live, initial testing entails testing the application’s current functionality. Final testing is carried out after the product has been released and client feedback has been received. This assists you in identifying any performance issues with your product before its release.

Advantages of Regression Testing

If we do not perform regression testing, we will have to redo the entire project if a bug is discovered. This means we’ll have to start from scratch and build the whole thing from scratch. This would take a significant amount of time and money.

Important Aspects of Regression Testing

#01 Automation

Automation is one of the most important stable features of any regression test suite. You can save time and money by automating regression testing.

If you automate your regression testing, you can schedule it to run daily. And if something goes wrong with the application, you’ll notice it right away. You can then quickly and efficiently resolve the issue.

Another benefit of automating regression testing is that it decreases human error. When people run regressions by hand, they frequently make errors. 

For example, they may inadvertently skip steps in the test script or fail to test a specific part of the application. However, they may even miss a bug entirely. However, using automation eliminates these errors.

#02 Test Coverage

Coverage is another aspect of regression testing. The percentage of lines of code covered by tests is called test coverage. If the execution path of a line of code is tested, it is considered covered. 

The greater the number of lines of code covered by your tests, the better. It ensures that your tests cover the most significant number of lines of code possible. 

This will assist you in identifying potential issues before they become major performance issues.

One good rule of thumb is to have 100% test coverage. But don’t be too concerned about getting a perfect score. Instead, concentrate on improving the quality of your tests. 

That way, even if you get to 100%, you’ll still find plenty of bugs.

When writing tests, you should always be on the lookout for situations where you aren’t verifying whether a condition is true or false. If you find such cases, you should modify them to ensure that the state is actual.

Read also: 5 Things To Keep In Mind While Doing Regression Testing

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What Is Retesting?

Retesting is the process of going over specific test cases that were discovered to have a bug or bugs during the final execution. 

Generally, these bugs are discovered by testers while testing the software application and are assigned to developers to be fixed. The developers then fix the bugs and return them to the testers for verification. This ongoing process is known as retesting.

Requirement For Retesting 

• When a specific error or bug needs to be verified, retesting is used.
• When the developers reject a bug, the testing department determines whether the bug is real or not.
• It is also used to test the entire system to ensure fully functional.
• It also examines the quality of a specific component of a system.
• When a user requests that their system be retested.

Procedure of Retesting

When a tester discovers a bug, the bug situation should be fresh, as the development team may or may not accept the bug. 

If the development team accepts the bug, it will be fixed and released in the next version. 

The bug’s status will be ready for QA. The tester will now verify the bug to determine whether or not it has been resolved. This is known as retesting in software testing, and it is a type of planned testing. 

We used the same test cases and test data in the previous build. If the bug is not found, the bug’s status can be changed to fixed. 

When We Do Retesting

#01 If A Relevant Bug Fix Is Mentioned In The Update Note

Before the new development team releases the latest bug, the test team must test the previously published bugs to ensure that they have been patched or not.

#02 If A Bug Is Removed

The production team also disregards a few bugs raised by testers and considers the bug status unreproducible. 

The testers must then repeat the problem to inform developers that it is valid and reproducible. To avoid this situation, we must write a successful bug report.

#03 If A Client Requests A Retest

To trust the consistency of the product, the consumer may frequently request that the test be replicated. 

In this case, test teams are once again examining the substance. However, we must never release a product after only making changes to the code to validate the bug fixes; we must also test for regression.

Types of Retesting

#01 Automated Retesting

Various regression testing tools, such as the built-in Selenium Web Driver, Cucumber, and others, can be used to automate software tests. 

These tools enable us to automate manual processes such as clicking buttons, filling out forms, and so on.

#02 Manual Retesting

Manual retesting is performed by testers who are aware of the current state of the software application. 

This includes knowledge of how the software works and how to use it effectively. Manual retests may be required if the application cannot be run under automation due to some reasons.

When Should I Retest My Application?

There are several reasons why you might need to retest your application. The first thing to consider is whether there was an error during the initial testing phase. 

If so, then you should perform a second round of testing. You should also retest if you add new functionality or change the previous functionality.

Comparison between Regression Testing and Retesting

What do they have in common?

Retesting and regression testing are both crucial aspects of software quality assurance, and while they have distinct purposes, they share some common ground:

• Repetitive nature: Both involve executing test cases multiple times. Retesting focuses on specific failed test cases, while regression testing covers a broader spectrum.
• Focus on quality: Both aim to ensure the software functions correctly and reliably.
• Part of the testing process: They are integral components of the overall software testing lifecycle.
• Potential for automation: Many test cases in both categories can be automated to increase efficiency and accuracy.

 What makes them different? 

• Any test – current or prior version functionality targeted – can benefit from retesting. The functionality of previous versions is the focus of regression.
• There is no requirement for retesting if there has been a change. Change is the focus of regression.
• On failed test cases, testers perform retesting, whereas they perform regression testing on passed test cases.
• Retesting ensures the rectification of the original error, whereas regression Testing ensures that there have been no unanticipated side effects.
• Regression testing has a lesser priority than retesting. Testers conduct regression testing parallel to retesting.
• Due to the ambiguity, we are unable to automate the test cases for Retesting. On the other hand, you can automate regression testing.
• Regression testing is generic testing. Retesting is a planned test. Regression is a broad topic with a variety of subtypes. Automation is also a good fit for regression testing. If your team is spending a bunch of time running the same regression test cases over and over, it may be time to automate them. The examples and differences mentioned above give us a better understanding of the differences between Regression testing and Retesting.

The Major Difference Between Regression Testing And Retesting

Retesting is the process of evaluating the performance of a system or component by reusing the same data that was originally used to assess it. 

On the other hand, regression testing is the process of determining whether a change has resulted in any unintended consequences. 

For example, a retest does not always imply a regression test. Therefore, it is possible to do so without modifying the codebase.

Regression testing compares an older version of software to a newer version of the software. This type of test aims to see if there are any issues in the newer version of the software that were not found during the previous testing.

Retesting is usually performed when a problem is discovered after a software release. The primary reason for retesting is that a new software version may introduce new bugs that were not previously identified. 

Retesting can also be referred to as “Defect Verification” or “Generic Testing.” Before releasing a new version of the software, it is common to practice to retest it. Retesting is typically carried out by testers familiar with the most recent version of the software.

On the other hand, regression testing is performed on older versions of software. The goal is to find unanticipated flaws in previous versions of software that the developers did not fix.

Retesting differs from regression testing in that it is carried out by individuals unfamiliar with the current version of the application. They are typically employed by the quality assurance department of a company.

Example

Assume you’ve written a program that computes the average of a set of numbers. Then you decide to include another feature in the program. 

To put this feature to the test, create a new test that checks whether the function’s average value matches the expected result. 

This test ensures that the new feature functions properly. However, you should also check if the original feature is still operational.

To accomplish this, you could either repeat the entire test or modify the existing test to ensure that the new feature does not interfere with the behavior of the original feature. If you choose the latter option, you are running a regression test.

Retesting Vs Regression Testing

Aspect	Retesting	Regression Testing
Purpose	To ensure that the software changes did not result in any regressions.	Find bugs, especially in older versions
Timing	After a software release	Before the software is released
Focus	Verify new features	Check for older bugs
Testing Approach	Typically manual	Often automated with tools
Goal	Ensure proper software function	Discover and report bugs
Usage	All software releases	Most recent software version
No Testing If No Errors Found	Yes	No
Importance	Ensures recent release is bug-free	Critical for bug discovery
Effort Requirement	Less effort	More effort, analyzing past issues

Conclusion 

If you’re still confused, think of retesting as checking to see if you fixed a bug and regression testing as checking to see if you introduced any new bugs with your fix. While you may find regression issues during a retest, they are separate and should be treated as individual types of testing.