Regression testing in agile ensures continuity of business functions with any rapid change in the software. In the agile context it helps the team to focus on the development of new features in the sprint along with the overall functionality.
Test automation and continuous execution helps achieve effective regression testing in agile.
Regression testing in agile helps to maintain stability in the software with every new product increment. Regression testing in agile is employed for better quality software delivery. With regression testing, we validate the existing functionality of the software is not impacted with any new modification to the code. These changes may include product enhancements, patching and the configuration changes or more. Regression testing aims at delivering bug free software.
Regression testing ensures that new changes have not introduced new bugs in the software. It can be employed with any localized or larger change in the software. Regression testing in agile is very essential due to continuous changes in the application and deployment of these frequent builds in agile. For a successful regression testing in agile, a testing team should develop the regression test suites in parallel to the development phase.
Regression Test execution in agile is performed through various regression testing methods. The approach we choose for regression depends on the test coverage, availability of resources for testing and the priority of an application to be tested.
Let’s talk about the regression testing techniques :
Retest All : It is one of the regression testing methods in which all the tests in an existing regression test suite are re-executed. This is costly as it requires more time and resources.
Regression test selection : In this method instead of selecting the entire regression test suite we select a part of it for execution. Test cases are categorized as : Obsolete and Reusable test cases.
Prioritization of test cases : The focus of agile teams is to deliver a working product to the customer at the end of every development iteration or sprint. Because the sprints are shorter in duration, it is essential to make regression testing efficient and quick too. This is ultimately achieved by assigning priority to the regression test cases and executing the high priority ones when the time allotted for regression testing is limited. The priority of the test cases is decided at the time of creation of the regression test suite considering the criticality and the business impact of the scenario being tested by a particular test case.
Regression testing, on its own, verifies if the previous functionality is working on expected lines along with the addition of any new feature. In agile development approach it implies that regression testing should ensure stable results at the end of each sprint by testing the impact of newly developed functionality on the application, thereby, ensuring smooth functioning of the overall system.
In an agile development methodology, new features are added every sprint and to ensure the proper functioning of all features at the end of every sprint, the regression test suite should be kept up-to-date at all times. Test cases corresponding to all the features that have been tested already and are stable should be added to the regression test suite regularly and test cases that are not relevant any more should be removed. All the test cases that need to be edited to keep them relevant with newly added functionalities should also be updated.
Thus, For effective regression testing in an agile way of working, it is important for a testing team to create regression test suites right from the initial development stage and keep on building the same as the sprints add up.
Refer here for information on regression testing approaches.
For proceeding with the execution of regression testing, a regression test plan needs to be constructed first. Below are few steps that play important role here:
Selection of test cases for execution.
Estimating the regression test execution time and outlining test cases that need to be automated in the regression test plan.
Identifying improvements for test case re design.
Regression testing in agile also concentrates on performance testing to ensure the system's performance is not negatively affected due to modification in the code.
There are different ways that regression testing has been adopted into agile. This mostly depends on the type of a product and the kind of testing it needs. There are 2 ways the test plans are constructed for regression testing in agile:
Sprint level Regression Testing: This testing focuses on executing only the test cases that have been after the last release.
End to End Regression Testing: This testing focuses on testing all core functionalities that are there in the product.
According to the level of development and stability of the product, any one of the above approaches to test case selection and test plan creation can be selected. For eg. Sprint Level Regression Testing makes sense when the development on a new release has just started and the product will take time to get to a stable version which can be tested end-to-end. End to End Regression Testing makes sense when the product is stable and the planned release is near.
In an agile scenario, there are also multiple approaches in which the Regression testing can be implemented:
Traditional regression testing approach: In traditional SDLC, regression testing is executed after the development and just before the testing phase is completed. In agile scenario, it is executed just before every sprint.
Delayed week approach: In this approach, regression testing can be delayed to the next week if the product was not stable for regression testing as planned. This is usually followed when the product development is in its initial stages and is not stable enough for much testing.
Delayed sprint approach: In this approach, all the functionalities are tested in one go. Here, regression testing for features developed in 2 sprints is done at the end of the later sprint of the 2.
To avoid spending a lot of time in regression testing, it is advised to automate it.
Automated regression testing in agile is not time consuming and hence is essential to achieve a good velocity that the agile teams strive to gain. Agile testing is a software testing methodology that follows principles of software development life cycle.
It's all about changes and making differences in requirements even in the future with better development phases. The main objective of agile testing is to deliver the product with minimal functionalities. Agile testing is a very rapid and dynamic testing process. Usually the sprint cycle is of 2-4 weeks in which the development is done for a new feature that needs to be tested and regression testing needs to be done for the old features from the previous release( the working project that was result of the last sprint) which went into production.
To perform smooth regression test execution, the testing team can build a test strategy before the beginning of the development phase itself and modify it with every upcoming sprint cycle. To begin with,Smoke and sanity testing can be the very first step in creating the regression test strategy plan.
Sanity testing is executing high priority tests to test the working of an application prior to the additional testing of new release to confirm functionality works as planned.
To perform smooth regression test execution, the testing team can build a test strategy during the development phase itself and modify it with every upcoming sprint cycle.
Steps for creating a Regression testing strategy are as below :
Create a regression test script and with every new update the test script can be modified and reviewed to verify its correctness.
The automation test script should target all the possible scenarios to ensure a bug free product delivery.
Test cases that cover the error prone areas(those which fail more often) should be included. Sometimes, some functionalities in the application are so error prone that those will fail even with the slightest modification in the code.
With every sprint execution, maintain a track of this failure test cases and include them in the regression test suite.
Good communication should be maintained amongst all the stakeholders. Testing team should communicate with feature engineers, product owners and developers to understand any change in the requirement to monitor and assess the same.
Analyze the defect report as with every test execution cycle the automated tool generates a test report that specifies the failed test cases, which step in the test case was affected which in turn affected a particular functionality. Error tracking tools also generate screenshots and failure metrics during regression testing. This helps in identifying and debugging the issue.
Aim to focus on the risk areas (non functioning of the existing functionality due to modification in the code) that compromise on the product quality.
In order to gain confidence on the quality of the product being delivered, It is important to deliver a product that is not only well tested but also properly tested for regressions. Implementing regression testing in agile ensures that the overall quality of product is as desired by the customer even with the addition of new features in the application every sprint.
Implementing regression testing in agile helps to build an overall stability in the software. Regression testing in agile, done at the right time, reduces the programming rework of products that might not work as expected due to inadequate testing.
Since manual approach to regression testing in agile is a time-consuming process, it's better to automate the regression test suites and perform the execution which eventually saves time and also increases the test coverage. With the availability of a variety of automation tools in the market, it is important to select the proper automation tool when it comes to automating the regression test suites. There are automation tools that offer codeless test automation. For more reading refer this guide to codeless testing.
The automated test cases created for regression testing can be reused in every sprint where regression testing is needed which can eventually save a lot of execution time.
While implementing regression testing in agile we need to prepare for regression execution as early as possible before the development phase ends. Regression test execution can then begin as early as possible after the development is completed. This helps us to stay within the timelines.
If the regression testing is automated, it saves the time spent by testers on regression testing and the testing team can focus on covering more areas of the software, performing different types of testing other than regression if any. If not, it can help achieve a quicker release.
With the increasing importance being attached to the quality of a product, implementing regression testing in agile guarantees a stable product at the end of the sprint every single time.
Nowadays, with constant decrease in time period between software enhancements and releases, testing teams are convinced to adopt regression testing in an agile environment that can keep up with requirements changes, feedback from production environments and more.
Achieving a high success rate with regression testing - regression test execution that reports more bugs - depends on the selection of test suites. For that, the test suites that cover major defect prone areas in the software should be given higher priority during test execution. Regression test suites should be developed as per the best practices to cover most important areas first. Regression testing, in an agile environment, is modernized to be performed on a daily/weekly basis for risk mitigation and to fit in the agile methodology goals.
Considerations for modern regression testing include focusing on maintaining regression test suites. These regression test suites (that include both critical as well as non critical functionality of an application) help in selection of test cases for test execution depending on priority and allotted time. Right selection of test cases results in regression testing that is efficient and effective.
Consider a group of test cases covering the functional as well as non-functional aspects of the software. Regression testing for this application can be performed as per the defined steps :
Determine the execution schedule for regression and the frequency of test execution on a daily, weekly basis.
Plan for resources well in advance to commit to the regression timelines.
Understand the time window to complete the regression tests as per the available resources.
Take into account the areas which trigger regression test suite improvement and maintenance. 5.Target to perform the sprint level regression testing as well as an end to end regression testing.
Target to perform the sprint level regression testing as well as an end to end regression testing.
The regression testing team should also perform the performance testing to ensure the system's performance is not hampered abruptly.
Once the testing is done, Agile teams can formally confirm on the completion of regression testing by proving DOD (Definition Of Done) tasks have been completed. DoD helps the Scrum team to identify all the valuable deliverables needed to complete the Agile project successfully on time.Definition of done, in terms of testing, specifies the conditions under which all the testing tasks - including test plan, test strategy, test case development, selection of test cases, execution time for executing the tests, tools for defect tracking - are considered completed.The Definition of Done ensures everyone on the Team knows exactly what is expected of everything the Team delivers.
Post regression completion, issues faced during regression testing can be addressed in the agile retrospective scrum ceremonies. These issues can be taken as the improvement points for which the testing team can define relevant action items. The testing team can actually create a story on the retrospective actions and start working towards the regression test suite improvement.
In order to adopt regression testing in agile it is important to consider certain key factors that also stand as the fundamentals for regression testing :
Consider selecting automated regression test suites that provide good test coverage.
With every iteration continuously update your regression test suite to cover functional as well as non-functional aspects of the software.
Sprint level regression test suites might vary with the regular regression test suites with respect to the objectives, functionality coverage, platform coverage and the timelines.
Listed below are the recommendations for agile regression testing :
Make a practice to differentiate the sprint level regression tests with regular regression testing cycles.
Ensure that the high priority high valued test cases are included in the regression test suite.
Decide on what basis test cases can or cannot be automated.
Agile forces continuous changes to the requirements and the feature, this means changes in the test code will also be required for regression testing.
Focus on selecting advanced automated testing tools that, along with the test execution, also generate a detailed report and the graph on the overall test execution cycle. These testing result reports help to assess the total ROI (Return on Investment).
Categorize the test cases based on the priority as high, moderate and low. Include the end to end testing flows under high priority test suite, the field level validations at a moderate level and the UI and content related tests at the low level.
Categorization of test cases helps the new tester in the team to quickly understand the testing approach and provide good support in expediting the test execution process. Prioritization of test cases also makes it easier for the testing team to understand what to execute, when to execute and in what sequence to perform the test execution.
Keep updating the regression test scripts regularly to accommodate these changes.
Focusing on the fundamentals and adopting these recommendations for regression testing in agile can be considered as a best practice for the agile teams.
Before you plan the regression testing in agile understand your business area with respect to the functional and technical requirements very well.
Following pointers can help us plan an effective regression testing :
Plan refinement sessions with all the stakeholders like the product owner, feature engineer, business analyst and the development team to address gap or unclarity on any requirement. This is the very first step before we start creating our initial test scripts.
It is important that, as new releases, updates and changes are rolled out, the regression test suite is updated to maintain the documentation of the business area.
Plan a walkthrough on the test cases created among the business owner and the stakeholders. Target to cover first the business requirements that define the most critical functionalities.
Test cases should be reviewed by the stakeholders in order to detect any miss in the functionality of a given requirement.
The testing team can create a traceability matrix to map the test cases against the requirements of a product. This ensures 100 % business requirement coverage which stands very essential and is much appreciated by the customers.
To plan an effective regression testing in agile one should determine and understand the correct testing approach as mentioned below :
The testing team should understand very well what set of test cases to be selected for regression testing in agile.
In case because of changes in code changes are needed in the test cases, we need to determine what needs to be changed specifically.
The objective of system integration testing needs to be clear to the testing team. The team should validate that all software module dependencies are functionally correct and that data integrity is maintained between separate modules for the entire solution. System integration testing should focus on the communication between modules not the functionality of individual modules (which is ideally tested in component testing).
We also need to be sure which parts of a functionality can be automated and if yes, how the automation will take place to have the test cases ready for execution.
To accomplish a successful regression testing cycle one needs to know the process of establishing an automated regression test suite. For e.g. Automate the end to end happy flow scenarios first such that basic regression testing for all scenarios can start soon.
On completion of regression testing in agile we need to analyze the regression test results that determine the success or failure of the feature.
On completing the regression testing, the team can prepare a lesson learnt document on the overall testing process and share it with the stakeholders to validate the quality of the testing process.
Since the agile way of working forces frequent changes to the software which in turn requires constant updates of the test scripts to maintain a smooth test execution process. The testing team’s knowledge of advanced automated tools and the process to automate the regression test suite could prove to be of great help.
Regression testing ensures more test coverage as it aims to execute test cases for all the features of an application.
Regression testing, in agile, when done properly - lets the teams know in advance about a defect in the software. This helps the developers to resolve the defect and prevent incidents on production.
Regression testing in agile helps to deliver high quality software to the customer by ensuring system stability while new features and bug fixes are added to the application.
Regression testing in agile is cost effective. Automating regression tests benefits the firm to keep the cost low by minimizing the team size. Resources can focus on more important tasks.
For any upcoming sprint cycle, the regression test suite of the previous cycle is readily available for the test execution phase. Such a software testing generates high ROI (Return on Investment) and is less time consuming since the entire testing is executed via automated tests.
Regression test cases are huge in numbers and mostly automated as executing them manually would be very time-consuming.
The effectiveness of regression testing depends on the selection of regression test cases for execution, which in turn depends on the criticality of the component or module.
In regression testing, to reduce the time taken, we need to focus on reducing the number of test cases by analysing the impact of newly added features on the overall application. This is done by selecting the test cases for the impacted area and executing the high priority test cases in the selected test cases.
To optimize regression testing in Agile methodology, efforts need to be put in from the start of development, below are few suggestions that can help:
The testing team needs to have seamless communication with all the stakeholders. Much before the regression cycle begins, the testing team should work together with the developers, business analysts and the product owners start refining the new feature. Business analysts can monitor the changes in the requirement to assess them from a testing perspective.
On closure of the requirement gaps, the testing team can design test cases based on the priority of an application. Once the features are stable, the corresponding test cases can be moved to Regression test suites. These test cases can be divided into high, moderate and low priority test cases. Ensure to cover risk based approach while designing the regression test suite in agile.
Automating the regression test suite saves a lot of time and effort needed in test execution. So, after analysing all the efforts that would go in and the results, if the ROI is positive, teams should invest in automation of regression testing.
Document the regression test plan that defines the testing scope, testing approach, testing techniques, types of testing (Unit/Integration/acceptance) the test environment details, entry and exit criteria for testing, risk requiring contingency planning, execution schedule, available resources, defect tracking tool, etc.
Follow a regular peer review process for the designed test cases.
Selection of high priority test cases for execution when the allotted time is limited leads to better test coverage and better bug identification in less time.
Involve all the stakeholders in the agile refinement session and plan a walkthrough on the test cases.
Adhere to the review comments and wherever required make necessary changes in the test cases.
Plan training sessions on the functionality of a feature as well as the automated tool before the regression execution begins.
Focus on clear communication during daily agile stand ups to raise any impediment in the testing process. Keep the product owners informed of the current regression execution status.
Agile methodology presents a set of challenges to their automation team as mentioned below :
Unclear business scope and minimal documentation are a challenge for automation testers to start with. In agile, each process re-iterates every 2-4 weeks and maintaining everything in proper documentation is not always possible. Keeping the automated regression test cases up-to-date with the latest features also requires dedicated efforts by the testers otherwise the test cases could soon deem themselves as useless.
Each agile release iteration takes between 1 to 2 months to deliver the changes into production. Sometimes there are changes that need to be captured at the end of iteration. These changes are so volatile that the iteration cycle gets disturbed. These changes are greater challenges in implementing automated regression testing.
Selection of proper automated tools is a major challenge. Automation in early stages of agile projects is a bit tough but as the system grows and evolves it becomes easy to deploy automation. So the choice of testing tool is a key aspect in agile testing process.
Resource management is the biggest challenge in automation testing in agile. Testers need to verify the new features developed and also perform regression testing at the end of the sprint to make sure that nothing else broke. Sometimes, there could be a lot of juggling in terms of tasks.
Good communication should be established between the automation team, developers, business analysts and stakeholders. Collaborative interaction between client and delivery team implies more suggestions or changes from the client. These changes can be incorporated in the application as soon as possible targeting to meet the timelines. Also, all challenges faced in the automation testing process should be discussed in the daily stand up meetings so that everyone is well aware of the existing issues in automation if any.
In the modern agile process, regression testing plays a very crucial role. In the world of competitive markets, every firm in the software development industry wants to step ahead of others with respect to building a much more advanced software.
Agile represents an incremental and repetitive development methodology. With the client demands and the frequent changes evolving around the software in the agile way of testing, regression testing becomes a very important and essential factor in the test life cycle process.
Agile requires that the developed software undergoes continuous testing and development. Along with incorporating the new feature in the software, the existing functionality of a software should not be impacted. Customers should be able to use the advanced software without any issues. To maintain software reliability we perform regression testing in agile.
Regression testing in agile gives a clear vision to all the stakeholders in the business on the delivered software post implementing the code changes. Regression testing in agile ensures the code changes done have not introduced any bugs in the software.
Regression testing in agile helps to mitigate the risk in the developed software. Regression testing is the means by which we assure the customer the final product delivered meets his expectations. Regression testing is the sub child of agile testing. It helps development teams concentrate on developing the new product while maintaining stability with every new product increment.
Complex software development in agile requires both efficiency in testing and quality to ensure any code changes do not impact existing features. Regression testing in agile forces continuous improvement in the application through the testing cycle.
Regression testing in agile is performed whenever there are bug fixes, requirement changes, system performance issues. Regression testing also determines the performance of the overall system. With the continuous integration in agile aiming at continuously delivering an efficient product, regression testing stands important to be performed in every release.
Regression testing in agile is performed by the testing team in close collaboration with the development team to ensure adherence to quality. Certain challenges can make regression testing difficult for agile teams.
Excessive requirement changes made by the customer can affect the entire regression test automation strategy. These volatile changes can impact the iteration cycle causing a delay in delivery. This is a risk to the overall testing strategy and planning. Regression test growth is one of the major challenges faced by agile teams.
Regression testing scale increases with every sprint and in larger projects regression might become unmanageable. For manageable regression cycles, the testing team needs to automate the test cases, frequently review the tests, update the test scripts whenever required and remove the ineffective test cases. This requires constant monitoring on the regression test scripts.
Sometimes due to lack of communication between the testing team, developers, business analysts and the stakeholders resources might fail to understand the correct requirements. With effective communication, everyone can have a common understanding on the changes to the product — new features and the one which requires new regression tests.
Lack of special testing professionals in the team can be the biggest regression testing challenge faced by the entire team. The testing team needs to be proficient enough to design test scripts that cover the requirement and test the overall functionality of the feature.
Regression test case maintenance is also important to perform an effective regression. Testing team needs to take into account the test cases are not loosely coupled that they may pass even when an issue exists.
Time constraints can be a challenge to the regression team in agile. Large and complex projects may demand additional regression test execution time.
The challenges arise when there is confusion about application development boundaries when they are not discussed with other teams. This might result in modifying the code that belongs to the other teams. As the developers won't have the end to end visibility of an application, it might populate additional bugs in the system.
Failing to optimize the regression test suite implies ineffective regression test cycle. Strong supervision on the regression test suites helps us overcome this challenge.
Regression testing in agile can be expensive at times due to unclear ROI (Return on investment).
Regression testing is a type of software testing to ensure that the recent code changes have not adversely affected the existing features of the software. Regression testing ensures smooth functioning of the overall software.
Common types of regression testing include :
Corrective Regression Testing : This type of testing is used when there are no changes introduced in the product's specification and the existing test cases can be used for performing these tests.
Retest-all Regression Testing : This involves testing all aspects of a software as well as reusing all test cases even where the changes have not been made.
Selective Regression Testing : In this type of testing, a subset from the existing test cases is used which reduces the effort required for retesting and the cost involved.
Progressive Regression Testing : This type of regression testing works best when there are certain changes done in the program specifications as well as new test cases are designed. This ensures there are no features that exist in the previous version that has been compromised in the updated version.
Complete Regression Testing : Complete regression testing is performed in case there are multiple changes done to the already existing code. On completion of this type of testing, the final system is made available to the user.
Partial Regression Testing : Partial regression testing is performed after impact analysis. In this testing process, the new addition of the code as a unit is made to interact with other parts of older existing code.
Unit Regression Testing : It is an important part of unit testing. Unit regression testing mainly focuses on the code unit and all the dependencies and interactions are temporarily blocked during the test.
Regression testing instills a sense of confidence in developers, project managers and stakeholders that after the changes are made in an application, the other unchanged features in the application are working as they should be.
No, User Acceptance Testing (UAT) is not the same as regression testing. In regression testing, testing is done on a modified software to make sure that any new changes that have been introduced do not hamper the functioning of existing features in the software.