January 26, 2017

How to Make Your Regression Testing More Effective

Software products undergo through numerous changes in their life cycle. When a change occurs in the product, regression testing becomes essential.

Failure to perform effective regression testing can cause a lot of needless suffering – it might happen that everything required in the new sprint is working fine, but the previously implemented features and functionalities got messed up. If this happens, the client would not appreciate you for the new functionality; he would become angry, irritated and can be a real trouble to handle.

In this article, we will briefly explain the regression testing and the scenarios in which regression testing is applied. We will discuss in detail the challenges a quality assurance manager might face while conducting regression testing. Later, we will see how we can devise an effective and efficient regression testing strategy to overcome those challenges.

Let’s have a quick look at regression testing definition.

What is Regression Testing?

The definition of regression testing, as stated in ISTQB glossary:

“Testing of a previously tested program following modification to ensure that defects have not been introduced or uncovered in unchanged areas of the software, as a result of the changes made. It is performed when the software or its environment is changed.”

When to perform Regression Testing?

Regression testing is performed when any of the following situation happens during software development lifecycle:

  1. A bug is fixed.
  2. A change in requirements is implemented.
  3. A new business rule, feature or functionality is implemented.
  4. A new module, component or subsystem is developed and integrated to the existing modules or system.

Challenges of Regression Testing

Regression testing is easy to define and understand, but baffling when it comes to perform regression testing of a software product. One reason is the dynamic nature of software product.

Further complexity is added as the product’s functionalities and capabilities expand. Lastly, the quality assurance team might also face time limitations and pressure from the management when they are testing the application for regression.

You need to understand the challenges well, before you can craft a counter strategy for those challenges. Let’s have a look at the common challenges of regression testing, listed below:

Knowledge of Existing Application

It happens that new testers join the team, as the workload increases. The new team members gain knowledge of the new modules, subsystems and components assigned to them. This knowledge might be sufficient for major functional testing, but insufficient for the regression testing. You can not perform complete regression testing with partial knowledge.

Hence, it becomes a challenge for the testers to deliver the knowledge of existing features and functionalities to the new members. Similarly, new testers are not very comfortable in gaining knowledge of what happened in the past.

Sometimes this reluctance is result of the fact that existing application already contains a lot of modules or subsystems, with myriad business rules implemented. At other times, the testers that tested the early versions of the application might leave the team and consequently no one in the team might have detailed, correct knowledge of early features and business rules.

In such scenarios, it is mandatory that a consistent test management and requirement management approach is followed so that new testers can also perform regression testing effectively.

Expensive for Business

Another challenge associated with the regression testing is the portrayal of its value to business people. It might happen that business units of the organization see regression testing as an expense to the organization with little value to the business. They might consider it a drain of resources and manpower to test again and again, something which has already been developed, tested and deployed at early stages. Hence, the management can be reluctant in allocating the budget, time and resources to conduct the activity of software regression testing. Hence, the management can be annoyingly critical and demand justifications for every cycle of regression testing.

As quality assurance manager, it is your duty to convince the management about the need and importance of regression testing. You will need to intelligently devise a regression test strategy which is efficient and effective. Remember that management is interested in giving you minimal resources, time and budget so make request accordingly and be prepared to justify your demand.

Less Time for Regression Testing

When testers are told to perform regression testing, they are tempted to perform exhaustive testing of the software product. However, the quality assurance team is not given much time to perform regression testing. Therefore, it is wiser of the quality assurance manager to make sure that the testing team does not exhaust all energies on a few modules – missing out the testing of other modules due to shortage of team. This means that the quality assurance manager needs to devise an intelligent methodology for regression testing to assure that every required test case has been executed within the limited span of time.

Easy to lose track

As new features and changes are implemented in the software product, more test cases are added to the regression test suite. As the product functionalities expands, testers are overwhelmed by the regression test cases and they fall victim to lose the track of test cases, overlooking the important test cases. This can be prevented by regularly monitoring the regression test suite and deleting the obsolete test cases. It is also important to avoid any duplication of test cases, else they will add to the unnecessary effort and frustration for testers.

Selection of Regression Test Cases

Selection of test cases for the regression test suite is yet another challenge of regression testing. You want to make sure that all points of integration and changes are being verified by the regression. At the same time, you can not overload your regression test suite with test cases as you get less time for regression testing. As a result, you need to choose the test cases wisely, regularly monitor the test suite and perform periodic cleanup for removing obsolete or unnecessary test cases from the regression test suite.

Another problem arises when there is a conflict of requirements. You need to be really mindful of the updated requirements and corresponding test cases. Any carelessness might result in retaining the test cases that have now become invalid and removing the valid test cases. Furthermore, make sure that all required test cases, for the new scenarios, have been created and moved to the regression test suite.

regression testing

How to make your Regression Testing Effective?

Phew! We just discussed the various challenges at every step of regression testing. Now, you must have become uncomfortable and looking for the ways to overcome those challenges. Do not worry! We have got a few tips for you that will help you formulate an effective regression testing strategy. You can improve your regression testing by incorporating the following elements in your regression testing strategy:

Closely Monitor the Changes

Closely monitoring of changes hold a vital importance in regression testing. We discussed that regression testing is performed when a change is made into the existing application. This follows that you need to closely monitor the changes in the requirements and their corresponding impact on the functionality of the application.  Upon doing so, you will need to modify the test cases in your regression test suite i.e. add new test cases, delete the obsolete test cases, modify any expected result or test steps.

New Test Cases for Impact of Changes

As new features and changes are implemented in the software product, they are integrated with the existing functionalities. These integrations can be really tricky and are most susceptible to the bugs and issues. This means that you can make your regression test strategy effective by analyzing the impact of changes and integrations of different modules, systems or sub-systems.

The tip is to identify the points of integration and analyze how the changes, new features or bug fixes might have impacted the older features and functionality. Create new test cases for testing and verifying the correctness of integrated application. These test cases can be added to your regression suite now.

Identify Problematic Areas

Another important step towards effective regression testing is to focus the problematic areas. Due to several factors, some modules of software have less bugs than others such as difference in complexity level of each module, expertise of the developer, clarity of requirements. This is also evident from the bug reports that some modules have larger number of issues, as compared to others. You can analyze the bug reports and identify major problematic areas. Similarly, you can analyze the user reported issues that occurred due to overlook in regression testing.

In this manner, you will get a clear picture of problematic areas and tricky integration points. This follows that you need to focus and prioritize testing of these risky features. Take special care that you don’t remove the corresponding test cases, during periodic cleanup of regression test suite.

Maintain Regression Test Suite

Maintain a repository of regression test suites. Whenever a new change or integration occurs, create respective test cases and add to the regression test suite. You can also move some of the existing test cases into the list of regression test cases. The goal is to maintain all test cases at one place which should be executed at the time of every regression test cycle.

Not all test cases qualify for regression test suite – you selectively choose test cases into your regression suite. Regular screening of test cases is one of the ways to ensure accuracy and efficiency of test suites. Optimize your regression test suite by the categorization of test cases into reusable, re-testable and obsolete test cases. A well maintained regression test suite can be really handy for performing effective regression testing.

Periodic Cleanup of Obsolete Test Cases

As we have discussed in challenges of regression testing that quality assurance team gets limited time, resources and considerable pressure from the management while performing regression testing. Therefore, it becomes essential for the quality assurance manager to conduct a periodic cleanup of the regression test suite. This will help the QA to keep their priorities correct and spend their time on executing the required test cases only.

For example, you can delete test cases of outdated requirements. Otherwise, there can be a conflict if original and updated requirements state two different things. Similarly, there is a possibility that you created test case for verifying the integration of two modules, say Module A and Module B, and have verified its functionality several times. Now, there is no change or requirement that could have impacted the functionality of integrated Module AB. In such scenario, you can remove the test cases that were prepared for verification of integrated Module AB.

Random Testing of User Scenarios

No matter how careful you have been while creating test cases and how many scenarios you have covered, nothing beats random testing at the end. Dedicate some amount of time to random testing of the application. These random tests might cover complete process cycles. You might also assume the roles of different users and try to depict real world scenarios as the users interacting with the system.

Rotate Your Workforce

This point is more linked to human resource management. The quality assurance manager manages the team of people, so he should also take care of the motivation level and interest of his team members. If you ask the same tester to perform regression testing every time, he may get bored, disinterested or develop the tunnel vision. Eventually, he will lose the motivation and the quality of testing might drop which means defects could slip through into live release. So, a better approach is to keep rotating your workforce and give different testers the task of regression.

What challenges of regression testing do you face? How do you overcome those challenges? How do you make your regression testing strategy effective? Do share your thoughts and feedback in the comment section!

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