Importance of Regression Testing
Agile is probably one of the most frequently used words in relation to application development. The term “agile” is used to represent multiple incremental and repetitive development methodologies. It essentially focuses on a continuous evolution of the software as well as the project. Therefore, Agile requires that the software being developed undergoes continuous testing and development. This is typically guided through Scrum, an agile framework to manage software development projects in sprints, which focuses on ensuring quality of the software application in relation to its’ design and implementation.
Development of complex software using an agile methodology requires both quality and efficiency in testing with each sprint to ensure that any code changes don’t impact pre-existing features and functionalities. This is where regression testing is extremely important.
As most applications continue to evolve after their launch, their maintenance and feature enhancements are key drivers in the continued success of the application. With organizations under constant pressure to launch frequent releases, this pushes both the development and testing teams to accelerate their processes. Regression testing helps ensure the continuous improvement of these applications and products through their post-launch lifecycle. Regression testing targets the complete set of business functions of a system and is performed whenever:
- Bugs are fixed
- Requirements are changed
- Performance issues are fixed
- A new module is added & merged with the existing module or system,
- Code of an existing module is refactored / restructured
Regression Testing Challenges
As development and testing teams need to work in close collaboration to ensure adherence to quality in each sprint of the development cycle, this presents a set of unique challenges for the testers:
- Complexity: With regular updates, the application becomes feature rich, and at the same time increases in complexity. The number of test cases in the regression suite will increase to cover all critical business features. In a complicated environment, it’s challenging for the team to focus on a specific portion while at the same time understanding the consequences and risks of these enhancements for the entire system.
- Time Constraints: In shorter sprint cycles, it’s challenging to retest the entire system along with the new changes. Regression testing may require additional time for complex and large applications. The team needs to focus most of their time during the sprint in regressing the entire system, which may increase time and costs.
- Optimization and Maintenance: Existing regression suites need to be optimized and maintained by modifying/adding test scenarios for any additional or removed application functionalities. These need to be completed in a particular sprint to meet testing time constraints which increases the challenge of carrying out optimization and maintenance. Test cases should therefore be prioritized based on the areas that are most prone to regressions.
- Cross-team Communication: To carry out end to end regression testing in agile, testers need to communicate with multiple stakeholders including business analysts, developers and project managers to understand how new modifications introduced during each sprint impact the application. The challenge arises when application development boundaries aren’t well defined between different teams, which may result in editing / changing code developed by another team. As the developers may not have end to end visibility, these code changes can introduce bugs into the application.
- Functional Test Cases are not Equal to Regression Suite: The common practice of including critical functional test cases of past sprints as part of the regression test suite might reduce the overall process and time needed, but the test cases may not reflect enhancements to those critical functionalities which were made after the earlier set of test cases was created. This results in duplicate functional test cases which would take more time for regression test execution and can also impact the overall quality score.
- Regression Testing can be Expensive: In most cases, regression testing may not have a clear ROI, therefore measuring the impact is difficult. It may be difficult for decision makers to sanction budgets for regression testing as it requires increased effort as the application goes through repetitive test procedures.
Best Practices to make Regression Testing more Effective
Let’s now look at how we can address some of the challenges above and continuously improve the effectiveness of regression testing methods:
- Strong Supervision:
The regression suite needs to be closely supervised and monitored in every sprint for changes to test cases. It is important to monitor the impact of modifications on existing functionalities by tweaking the test cases in the regression suite. This ensures proper usability and effectiveness of the test cases in regression testing.
- Periodic Updates in Regression Suite:
As previously discussed, QA teams generally have limited time to conducting regression testing, so it is crucial to have a regular assessment of the regression test suites to optimize and ensure accuracy and efficiency. A well-maintained and organized test suite will help the QA team to perform effectual regression testing in a timely manner. This helps to set priorities and execute only the required test cases. A risk-based approach can be used to make regression testing more effective by categorizing the test suite based on the priority level—High\Medium\Low.
Proper communication between teams working on common features will help the testing team to perform an impact analysis more efficiently, and in turn, help them write the proper test cases to support their impact analysis. This will reduce any confusion during regression suite testing.
- Optimize and Maintain Regression Suite:
Optimizing and maintaining the regression test suites is crucial. The following steps reduce the time and cost required to create and execute the same regression tests repeatedly.
- Development of Regression Suite:
Some functional tests may need to be upgraded to the regression suite which tests business functionalities better than existing tests to ensure that those tests cover an end to end scenario and not just the specific functionality. It can happen when the existing cases from regression suite are used in the sprint, as needed, with small tweaks.
- Automate Regression Suite:
With the right automation tool, execution time of the regression suite will be significantly reduced. Utilization of Smoke and Sanity testing automation techniques can also make a notable impact. Smoke testing involves early superficial testing of an application to confirm smooth operation. Sanity testing, as part of regression testing, focuses testing efforts on a few areas of the application. The advantage of automated regression testing is that more test cases can be added to the regression pack without affecting the testing time required.
- Rotate Resources:
The QA Lead should rotate tasks among the workforce, i.e. giving different testers the task of regression as sprints progress. Without this rotation, team members will lose interest while monotonously testing the same features, leading to a decrease in testing quality. Rotation of resources will encourage and motivate the team as well as maintain effectiveness throughout the regression testing process.
In an agile environment, regression testing plays a vital role to ensure critical functionality is maintained during system modifications. Regression testing acts as a safety net by catching any bugs introduced during the latest feature enhancements or new feature additions and also allows the testing team to focus on key functionality within the current sprint. Also, a well-managed and automated regression test suite gives confidence to the stakeholders and testers for sprint sign-offs. Contact us to review how you can use regression testing to provide continuous improvements in testing and a consistent user experience.