Presenting Regression Testing Tutorial!

Web App Testing

Monday March 11, 2019

Changing your code? Does that means a new round of testing and hours of work in creating test cases, executing test cases, managing test results, etc.???

The simple solution to this problem is Regression testing.

What is Regression testing?

REGRESSION literally means return or reversion. It is an act of returning to a previous state. In software terms, it is a testing that ensures that changes made to the system does not adversely affect it. Any changes done to the software are likely to impact the functionalities of the code.

Therefore, regression testing is done to assure that changes in the code have not altered the expected working of the software.

It does not require creating new test cases hence saving both time and efforts. In regression testing existing tests cases are rerun to validate the working of your software. So, be assured that you conduct regression testing whenever you change your code.

Let’s move forward and learn a little more about regression testing.

Types of Regression Testing

Regression testing is broadly divided into

  • Unit Regression
  • Partial Regression
  • Complete Regression

#1) Unit Regression Testing:

In unit testing, a single code or unit is tested while blocking any dependencies on that code/unit.

#2) Partial Regression Testing:

Partial regression tests the code that has been changed while it is united with the unchanged code.

#3) Complete Regression Testing:

It tests the complete code. It is done when more than one module is changed and its impact on the rest of the code is uncertain.

Importance of Regression Testing

In such a dynamic software field and heaving AGILE methodology; you will have to constantly upgrade your product to meet the latest demands of the users.

To assure that these changes do not affect the existing working of your software, it becomes mandatory to carry out regression testing. Regression testing can help you eliminate a lot of threats that are linked with software updates.

When to carry out Regression testing?

You can conduct this testing at any level of testing be it Unit, Integration, System, or Acceptance, but it is more appropriate to conduct it during system testing.

Know More: 50 Quick Ideas to improve your Software Testing Process

The extent of regression testing.

Should you rerun the test cases on the full code?

Though a full regression test is desirable, but it does take a lot of time. And when you are short of time, it is suggested to do an impact analysis of the changes.  Recognize the area that has the highest probability of being affected by the changes. And you can then conduct your regression tests for that particular code.

Difference between Regression Testing and Retesting

Are you confused between retesting and regression? The fact is that both are entirely different. While Regression testing ensures that any update made on the code does not affect the existing functionality, whereas Retesting, is carried out when test cases find some defects in the code.

And when those defects are fixed, the tests are done again to check whether the issues are resolved.

Retesting is to ensure whether the defects are resolved, whereas regression testing detects probable defects caused because of the changes done in the code.

Challenges of Regression Testing

Regression testing forms an important phase of STLC but brings along several challenges for the testers.

  • Takes a lot of time: it is time-consuming, it requires rerunning a complete set of test case again for a complete or some particular set of code.
  • Complex: Updates makes your code more complex, they even increase the set of test cases for regression testing.
  • Communicating Business Value: Regression testing ensures that updates bring no flaws in the existing code.  But considering the time taken to complete regression testing, it becomes hard to make non-technical clients understand the value of regression testing.

Best practices of Regression Testing

While you carry out this testing, the following best practices can help you get the best results:

Game Testing

  • Are you updating your regression testing test pack regularly?

Regression test pack is a set of regression test cases build keeping in mind the older version and their functionalities. With each new update, few new test cases are added. To avoid any future delays and rework, always keep your regression test cases pack updated.

  • Are you focussing on Main Features?                                    

Your code comprises certain functionalities that are most used by the end customer. Identify these core functionalities and make sure that your regression test pack includes test cases for these functionalities.

  • Are you focussing on successful test cases?

Make sure you include the test cases that have previously found bugs and defects in code.

  • Automate:

Automating regression testing is one of the best practices in regression testing as it frees the testers of boredom of carrying out the same test cases again and again.

 How to choose test cases?

Choosing the most apt test cases in regression testing is very important. Test cases in this testing keep growing with the evolution in software. The increased number of test cases results in cost and time increment to accomplish the complete set of tests.

With regression tests minimization, selection and prioritization, you can effectively reduce the size of the test set while retaining the value of regression testing.

Test cases minimization eliminates redundant test cases to reduce the number of test cases. Test case selection identifies the test cases having relevance to recent changes.

In Test Case prioritization, order test cases in a way to maximize early fault detection.

You can select your test cases based on the following conditions:

  • Frequently used Functionalities.
  • Test cases for the module that is changed.
  • Compound test cases.
  • Test cases covering major components.
  • Test cases testing core functionality.
  • Successful test cases which have discovered the defects.

Regression Testing Techniques

You can carry out this testing as per your requirements. Here are the various techniques you can leverage for regression testing.

  • Retest all
  • Test Selection
  • Test case Prioritization
  • Hybrid

#1) Retest all:

In Retest all you have to rerun all the test cases in your test suite. This technique is more expensive and more time consuming as compared to other techniques of regression testing.

#2) Regression Test Selections:

Keeping in mind the code change in the module, in Test selection technique you have to select test cases from your test suits that you have to carry out your regression testing on.

#3) Test Case Prioritization:

Based on the importance of functionalities, you need to prioritize the test cases into the top, medium and low priority. These test cases are then run based on priority.

#4) Hybrid:

It is a mixture of Test case Prioritization and Regression test selection.

How to Perform Regression Testing? 

The scope of this testing keeps increasing with the addition of new functionalities and changes in the code. Keeping in the mind the scope of regression testing testers prefer to use automated tools for regression testing. But you can also carry it out manually.

Steps to follow while performing this testing.

  • Recalling the above discussion–“How to choose test cases”, prepare a test suit for your regression testing.
  • You can choose to automate these test cases.
  • Keep updating your regression test suit, as and when required.
  • Execute regression test suit, whenever there is any code change, bug detection, functionality update or whenever a situation arises to retest your code.
  • Make a test report with the proper status reporting.

Tools For Regression Testing

Because of the high importance of this testing method in today’s world, a lot many regression testing tools are available in the market to ease up your task. Know more about some of the best regression testing tools in the market:


Always make sure you conduct a regression test on your code, whenever you make any change to it, how so ever small it may be. Assure the best quality to your clients with enhanced regression testing.


Hire a Tester


Call Us