Advantages of Regression Testing

Regression testing is the critical need in the agile competitive market. The software market growth depends on the regression testing success rate. Where functional tests ensure the proper functioning of the software, regression testing needs to be run to ensure applications stability during each sprint at every stage.

The many advantages of regression testing gives the target users an assurance that the new code changes are not affecting the existing features in the software. The Agile DevOps team can't compromise on skipping the regression cycle as the bugs will be encountered by the end users. This becomes a threat to the reputation and credibility of the software industry.

The testing team needs to be well aware about the advantages of regression testing that makes regression testing essential in every test cycle.

  • Regression testing plays a crucial role in an agile environment where with every sprint, the integration of previous and the current release has to be ensured. Regression guarantees continuity of business operations.

  • Regression testing ensures even with these constant additions, the application strives to remain intact and integrated. Automated regression tests generate faster results and enable repeated testing for similar releases. This helps to track any kind of error in an application on a constant basis.

  • It helps to gain customer faith and thereby achieve higher CSI(Customer satisfaction Index) and eventually can be considered as a major reason to expand the business.

  • Regression testing ensures a fix does not adversely impact the existing functionality. Along with pushing the new additions to software in the production, the team ensures the existing features remain unaffected.

  • Regression testing also helps implement a continuous integration setup in which whenever the developer pushes a code, a build is triggered post which the regressions test suite is automatically executed to ensure smooth functioning of the entire software.

  • It promotes the improvement of the product quality, and it verifies that any modifications that have been done to not impact the core functions already tested and proven.

  • Regression testing outweigh the risks of skipping it.

  • Regression testing helps to identify the bug in the software by catching the undefined integrations between the modules in an application. With regression tests, the software is made resistant against discrepancies. This provides support to the testing teams to release the product faster with quality assurance.

  • Automated regression testing substantially increases the testing process and shortens the testing lifecycle. Automation scripts can be run overnight as well across various machines at the same time period. Once the automated regression test suite is ready and can be utilized for execution, the test resources can focus on other needed areas of the application that require their expertise.

  • Regression testing helps to reduce unnecessary expenses that call for incidents in production. The cost of the overall project is also minimized by using automated software testing solutions.

  • Automated regression test cases save a lot of time in execution as same automated test scripts can be reused for testing and modified on need basis.

  • Regression testing can be performed both manually and by automation. Ensure to have a process in place for updating the regression test scripts as per the business objectives. Adopting automation in regression testing can save project cost to a great extent. Automation is ranked as the main advantage of regression testing.

  • Regression testing allows to detect and fix the bugs in the software before being shipped to the market.

Understand these advantages of regression testing and fully regression test your application to avoid issues in production.

When does regression testing occur?

Regression testing is always driven by change - change in terms of the application under test. If there is a change in the code, regression testing at some point of time is essential to avoid a regression.

Regression testing should occur in case of the following scenarios :

  • Regression should be performed on every single build that is deployed to avoid the issues from reaching the user. Another reason is, if a bug is identified soon after it is introduced corresponding to a commit, the developer will have a better chance to fix it. Automating the regression test suite helps us achieve this goal in much less time.

  • Begin the regression cycle during the start of the second round of testing, i.e. when the defect fixes start rolling in. This will help to ensure that existing functionality is not impacted by the scope, change / new feature.

  • Regression testing (Retest failed test cases) also occurs post retesting of a fixed bug. There's a possibility while fixing bugs and performing some code modifications, other portions of code is also affected. This eventually disturbs the operation of the existing features of the software. Hence, one round of regression testing is needed post defect retesting to ensure smooth functioning of all the features of the software.

  • Regression testing is performed when there is integration between two or more modules. Here, regression testing ensures the software product works flawlessly after integration with another product.

  • Regression testing occurs when the code is migrated on an advanced technology platform. Whenever there is a critical bug identified in the testing phase and fixed by the developer, post the fix, regression testing is essentially to be performed.

  • After any patching activity it's quite possible the existing functionality is not working on expected lines. Regression testing is important to be carried out after every patching activity.

  • Begin the regression cycle during the start of the second round of testing, i.e. when the defect fixes start rolling in. This will help to ensure that existing functionality is not impacted by the scope change / new feature. If your regression test suite is complex and large, you need to prioritize the test cases to be executed.

  • Regression testing happens whenever the DevOps team is expected to deliver a new feature to production. The team ensures along with the additional features the existing ones should also function smoothly.

  • Regression testing in agile also occurs when the developers rebuilt the existing functionality as per the latest technology for eg. a service which was developed in Tibco technology is now being rebuilt using Java. In such situations, regression testing checks whether the feature or service in question was modified with no damage to the rest of the functionality.

  • Regression testing is performed whenever there's a change request (CR) initiated by the client which requires code changes in the software.

  • Whenever there are performance issues or application crashes concerns reported by the customer, regression testing is much needed here.

  • Regression testing is also to be performed when the UI(User Interface) of the application is changed to make it more user-friendly.

Automated regression testing is ideally recommended under the following circumstances :

  • As often as possible for a stable build every single time.

  • Automated regression testing needs to be part of the build process. Ensure the tests are executed on regular intervals based on the build cycle, cost of execution, and result investigation. This set of regression tests needs to be executed and maintained through the entire development cycle.

If your regression test suite is complex and large, you need to prioritize the test cases to be executed. Focus on testing only those areas which are directly impacted by the scope change.

The problem with regression testing

Let’s discuss the problems with regression testing :

  • The major issue with regression testing is the stringent timelines. With every change in the software, the testing team needs to ensure the existing functionality is not adversely affected in any sense. The regression test cases have to be executed repeatedly within the reduced regression cycles in sprint.

  • Optimizing the test cases in regression testing sometimes is difficult. As the scale of regression testing grows with every sprint, more number of automation test cases are difficult to maintain. It becomes necessary to accommodate these changes in the regression test cases.

  • Even with automation, regression testing involves running existing test cases multiple times. It takes a lot of time to complete the regression cycle. With every new additional feature, the number of times the amount of regression testing to be done only increases.

  • It might be difficult for someone new in the team to intervene halfway to understand what is being changed and what is being affected.

  • Lack of communication between cross functional teams during regression testing also leads to problems.

  • To perform smooth regression testing, the environment in which the testing is to be done has to be stable. Environmental issues while regression test execution can simply delay the execution process. If this happens on a regular interval we might also compromise on the concentration of testers to identify and report bugs.

  • Identifying the test cases in every module a change is made takes time, it is very likely that we miss to consider the test case which is critical to validate this change. It's very time consuming to figure out the test cases to be executed in the regression cycle. It is quite possible while choosing and selecting the test cases for execution, we might miss to check the critical functionality.

  • Testing in the midst of code changes is not easy to implement and maintain.

  • The selection of the right automated tool also matters before we begin regression testing. Record and playback tools often don't work well in automated regression testing since it involves a lot of rework.

  • Regression tests need to be scripted and run on an automatic build environment. Automated regression tests need to be integrated within each sprint to work on the feedback continuously to address the defects as and when they are introduced to avoid late hardening sprints.

  • Regression tests need to be run after every development iteration and also after changes are made. There could be a lot of application stability or deployment issues observed during regression. This can slow down the overall testing.

Regression testing strategies of mobile web pages

In the era of digital transformation, users are mostly using mobile applications to access any feature online through mobile phones. Organisations are designing websites and applications keeping the mobile first approach as their primary objective. Having proper regression testing strategies in place define the success of mobile web page applications in the market.

Let’s discuss in detail how can we develop regression test strategy for mobile web pages :

  • As entry criteria is the set of conditions that an application should pass before the regression begins, the agile teams should develop entry and exit criteria for regression testing of mobile web pages.

  • Track the defects on a defect tracking tool, this will prevent the testers from raising duplicate defects and also track the overall testing progress.

  • Ensure to execute all the designed test cases because our aim is to achieve maximum test coverage.

  • Ensure to properly test the high risk areas. Some issues in the application are hard to catch with automation means. The testing team should possess good knowledge on the functionality of an application to identify as many defects as possible.

  • Perform manual exploratory testing on the application for modules or functionalities which are not possible to automate.

  • The agile team should focus on optimizing the automation test cases designed for an application. The regression suite should consist of old as well as new test cases.

  • Agile teams should document the defect report in detail with reference of the screenshots of the issue as well. The screenshots can be arranged in the defect in such a way that it also helps the developer to understand and replicate the issue very well in order to fix it.

  • The agile team should document the defect that is repeatedly identified in every regression cycle. Create test scenarios and test cases that are specific to the defects and get it reviewed by the test lead before the test execution phase.

  • Have a defined exit criteria in place. Exit criteria is a set of conditions that should be met before the regression testing phase is concluded. The testing team needs to define certain pointers in the test planning document and ensure all are agreed upon before the regression test cycle ends.

  • Critical reported bugs should be fixed and tested on priority.

  • Team can raise questions in the agile refinement sessions if there’s any uncertainty on the business requirements. This helps the team to avoid writing duplicate test scenarios.

  • The agile team should also take into account the compatibility testing for regression testing of mobile web pages. Compatibility testing includes to initiate a test flow from the mobile web page of the application, complete it by navigating through online banking and vice versa. For example add a payee from a mobile web page and modify the payee details through online banking. This enables the user to access the application as per his convenience which in turn increases the demand for the product.

  • The agile team should regularly update the regression pack to remove the unwanted test cases designed for testing the obsolete functionalities. Focus on designing the test cases taking into account the risk associated with the domain as well. For example :
    1. In a mobile banking application, test scenarios should be included that check how robust the app is when it comes to security. 2. For shopping applications that experience high website traffic, test scenarios should be created to test the performance of an application as well. Post the test execution completion in the buffer time, the testing team can perform random adhoc testing. This requires good insight on the application to be able to trace bugs from the perspective of an end user of an application.

Regression testing of mobile web pages is very essential to avoid application crashing or breakage of important applications when the live application is used by the user. Without proper procedure of testing it's quite possible that the regression testing team might fail to implement a smooth regression test cycle. Hence it is very essential to have a test strategy in place for testing the mobile web applications at both android and iOS level.

Benefits of Regression testing

Listed below are the benefits of regression testing :

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Disadvantages of regression testing

  • Manual regression testing requires a lot of human effort and time and it becomes a complex process. If automation tool is not being used for regression testing then the testing process would be time consuming.

  • Regression testing needs to be done repeatedly each and every time in the agile sprint.

  • In regression testing we aim to achieve maximum test coverage with the creation of limited test cases. This becomes difficult when we have stringent timelines

  • It becomes difficult to track the test execution time when there are changes in business requirements that are communicated in between the sprint and are to be delivered on priority So the scrum teams need to be prepared to accept the late change in requirements.

  • If the testing team does not understand the software development methodology they have adopted, there will be issues in planning the regression testing.

  • If the regression testing team does not possess adequate information on the application and the business requirements it will be difficult to perform a good regression testing.

  • It's a big challenge to perform regression testing under the time and resources constraints.

  • Regression testing has to be performed for every small change in the code as even a small portion of code can create issues in the software.

  • For complex functionalities we need to design huge test scripts which take a lot of time to execute. This might delay the test execution process and the testing team might fail to meet the delivery timelines.

  • It becomes difficult for the testing team to determine the frequency of regression tests after every release and build of bug fixes.

  • Lack of understanding on the business requirements leads to improper creation of regression test suites. If we don't have proper regression test cases in place the testing team might miss on testing and reporting the critical functionality defect.

  • If the testing team does not understand the purpose of regression testing they follow wrong steps in the regression test execution process.

  • If the testing team has done bad impact analysis or has no clarity on the changes in software it will be difficult to achieve good test coverage. This will eventually result in bad regression test execution.

Importance of regression testing in software development

  • Regression testing is the major and important part of any software development as it checks the complete functionality after the newly added feature has been verified to be stable.

  • Agile methodology increases the risk visibility at an early stage of the project development life-cycle. Regression checks the stability of the system after new additions to it. So, the importance of regression testing in agile methodology for software development grows manifold.

  • Finding and reporting a defect at an early stage of software development prevents excessive rework. This ultimately helps the testing team to meet the release timelines and deliver bug free software.

  • Regression testing helps the team to identify the defects and eliminate them earlier in the software development life cycle. It eventually improves overall user experience for the developed software.

  • Regression testing ensures continuity of business functions with any rapid change in the software. Also since automated test cases saves the execution time, the testing team can focus on covering more areas of the software.

  • Regression testing verifies if the functionality is working as previously after the new changes are made to the software.

  • Regression testing aims at performing continuous testing. Continuous testing helps in the overall quality and stability of the software.

  • As regression testing begins at an early stage it decreases the probability of missing the hidden requirements.

  • Regression testing is one of major factors in gaining customer confidence by living up to their expectations in terms of delivery and software quality. Organisations can showcase their ability in terms of efficient software delivery by adopting regression testing process in the test cycle.

  • With the increasing demands for the quality of product, implementing automation regression testing in agile guarantees faster shipping of the product to the market.

What is regression testing ? - explained with an example

For example :

  • In an online banking application, under the bill payments section there is a new feature of "adding a payee" that needs to be implemented to enhance the product quality.

  • The testing teams need to create test cases to test this newly added functionality in the application.

  • The testing team will perform the execution of all these existing modules in the regression cycle.

  • Also once the “Add Payee” feature is stable, for any feature the “Add Payee” feature test cases will also be added to the regression test suite.

  • In an online banking application, under the bill payments section there is a new feature of "adding a payee" that needs to be implemented to enhance the product quality.

  • The testing teams need to create test cases to test this newly added functionality in the application.

  • The testing team will perform the execution of all these existing modules in the regression cycle.

  • Also once the “Add Payee” feature is stable, for any feature the “Add Payee” feature test cases will also be added to the regression test suite.

What are the risks in regression testing ?

In order to achieve good automation regression testing results, the testing team needs to be proficient enough to possess good knowledge on the automation test techniques right from selection of tool and creation of automation test scripts to perform the test execution. Lack of automation expertise in the team can lead to a bad automated regression testing.

Let’s try to understand the risks associated in regression testing with an example :

  • Many times there is a customer who needs to rebuild an existing application built on a certain technology to a more advanced technology platform.

  • There are chances that the testing team does not hold sufficient knowledge on the functionality of an application. In such a scenario there is high risk involved as the regression testing can go haywire due to lack of application insights.

  • After several years , the software is bound to be enhanced so many times by the team who were not involved in the original development.

  • These kinds of changes make the system grow more complex until it becomes brittle.

  • The system level dependencies are difficult to be understood by the team. As the team is uncertain on how to test the application, it ultimately results in insufficient test coverage of the system.

  • The developers will implement the functionality using the advanced technology and hand it over to the testing team for testing purposes.

  • The regression risk grows exponentially as the application ages.

  • Even if the recent team did their best to understand the underlying design and structure , it’s very unlikely the changes they incorporated in the application fit with the original design theme.

  • The size of regression suite increases over time as the system grows in terms of functionality and complexity. Each new release faces the same constraints in terms of budget, schedule and team size. The complexity of the system is increased as more and more code is developed for new features and the interaction of various modules in the system increases.

To be able to overcome these risks and challenges in regression testing, the team can come up with a risk based testing plan that helps to assess these challenges.

How to manage risk in regression testing ?

Agile teams are responsible to make incremental delivery which means as the number of iteration increases, the size of the product also increases significantly. Hence the risk of regression is proportional to the product. As the product size increases , the risk of regression as well increases.

The testing team needs to be prepared in advance to have a proper plan in place to mitigate the regression risk. Having extensive automated regression test suites can definitely help mitigate the risk. In every iteration the testing team needs to keep on updating the automation test scripts. The automated test cases can be stored in the configuration management tool so that it becomes easier to retrieve on need basis.

If the test cases history is available to the testing team, it benefits the team in troubleshooting any major problem. The testers at the beginning of the test execution can prepare a test strategy document specifying how the regression testing needs to be carried out. The testing team needs to review the tests written earlier in order to be able to add, update or delete any test script.

Post regression testing team can plan a sprint review with all the stakeholders and give a demo of the developed and tested application and further retrospect on improving the same based on the suggestions received. Certain prerequisites like generating test data, test data loading, build deployments can also be automated to minimize the risks.

Using a risk-based testing strategy will significantly reduce the regression risk that stands inherent in making small changes to a large system.