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Change-Based Testing: Strategies for Software Success

Headshot of Jamie Motheral, Product Marketing Manager at Parasoft
November 21, 2023
7 min read

Dive into the role of change-based testing in software development. Read on as we unravel details about it, including benefits, tools, and best practices that can empower software development teams.

In software development, change is not merely an inevitability, it’s one element that keeps software systems relevant, efficient, and resilient. So, as technology advances at a relentless pace and user demands grow increasingly complex, the ability to adapt and evolve software becomes paramount. This is where change-based testing (CBT) comes in: a strategic software testing technique that checks for specific modifications made to the codebase to ensure that they do not introduce new errors.

Change-based testing is not a novel concept, but its prominence has grown substantially in recent years. In the past, software testing primarily focused on static, pre-release assessments aimed at finding and addressing defects. However, this approach often falls short when dealing with the dynamic nature of modern software, where change is constant and inevitable. In other words, the rise of Agile and DevOps methodologies, rapid development cycles, and continuous integration practices have all reinforced the need for a more adaptable, proactive, and on-the-go testing strategy.

Therefore, with change-based testing, there’s a fundamental shift in how we validate software, especially for large and complex systems. Instead of waiting for defects to surface in production, this approach tends to assess the impact of changes on existing code, ensuring that each modification is rigorously tested to maintain overall system stability.

Understanding Change-Based Testing

Change-based testing is a software testing methodology that revolves around assessing and verifying the impact of specific changes made to a software application during its development or maintenance. This approach is in contrast to traditional testing, which involves retesting the entire application from scratch. The primary objective of CBT is to identify and confirm that the alterations made to the codebase do not introduce new defects or negatively affect the existing functionality. It offers several advantages, including improved efficiency, quicker testing cycles, and enhanced test coverage.

In CBT, the first step involves detecting the modifications that have been made to the codebase, including changes in the source code, configuration settings, and database schemas. This is typically done using version control systems like Git or automated build tools. Once these changes are identified, an impact analysis is performed to understand how these modifications might influence different parts of the software application and its associated dependencies. This analysis helps in selecting the most relevant test cases.

After the impact analysis, you need to create or select test data that are relevant to the specific changes being made. This data is used to execute test cases that target the modified code or features. These test cases are designed to target the areas of the application that are likely to be affected by the changes, saving time and resources by avoiding the unnecessary execution of tests that are unrelated to the alterations. The selected test cases are then executed, and the results are reported. Any defects or issues discovered during this testing phase are reported to the development team for resolution. Furthermore, change-based testing incorporates regression testing, which involves re-running a subset of existing test cases to ensure that the changes have not inadvertently impacted other parts of the system.

Benefits of Implementing Change-Based Testing

Implementing change-based testing offers numerous benefits for software development and quality assurance processes:

  • Efficiency. Change-based testing enhances testing efficiency as it targets only the specific areas affected by code changes. This means that instead of retesting the entire application, which can be time-consuming and resource-intensive, only a subset of test cases related to the changes needs to be executed. This approach reduces redundancy, accelerates testing cycles, and enables faster development iterations.
  • Faster feedback. Rapid feedback to developers is often looked down upon in software testing. With change-based testing, developers can quickly ascertain whether their modifications have been successfully integrated and whether they have introduced any defects in the process. With this immediate feedback loop, developers can address issues promptly, preventing the propagation of errors and reducing development cycle times.
  • Reduced resource usage. Change-based testing conserves testing resources since only the test cases relevant to the code changes are executed. This is particularly valuable in large-scale projects with extensive test suites, where running a full regression suite for every change can be resource-intensive. When only the relevant test cases are selected for testing, it saves cost as well as helps testing teams allocate their resources more efficiently.
  • Increased developer productivity. When defects are found in the later stages of development, the developer’s ability to focus on writing new code is often disrupted for defect analysis and remediation. Change-based testing enables developers to work more efficiently and confidently, knowing their changes have been thoroughly tested before integration. Minimizing disruptions boosts developer productivity and morale.
  • Greater confidence in code changes. Change-based testing instills confidence in developers and stakeholders that code modifications will not negatively impact the software’s stability. This confidence can lead to more frequent and innovative software updates.
  • Enhanced software quality. This is probably the most significant benefit of change-based testing. CBT contributes to improved software quality by ensuring that code changes do not introduce new defects or negatively impact existing functionality. It plays a crucial role in maintaining the stability and reliability of the software. The focused testing approach helps in catching and fixing issues early in the development process, reducing the risk of delivering subpar software to end users.
  • Agile and CI/CD support. Change-based testing is well-suited for Agile development methodologies and continuous integration/continuous delivery (CI/CD) pipelines. In Agile environments, where rapid and frequent code changes are the norm, change-based testing helps ensure that software updates can be released without compromising quality.
  • Cost savings. Implementing change-based testing can lead to cost savings in multiple ways. It reduces the time and resources required for testing, minimizing expenses associated with extensive test suites and regression testing. Early defect detection and quicker issue resolution also save costs by preventing defects from reaching later stages of development or production, where they can be more expensive to fix.

How Does Change-Based Testing Contribute to Software Development?

Below are some of the ways change-based testing contributes to software development.

Validation of Changes

Change-based testing ensures that any modifications or additions to the software meet the intended requirements and do not introduce defects. This is crucial for validating new features or bug fixes. When testing efforts are focused on the specific changes made, developers can quickly ascertain whether the changes function correctly and align with project goals. This practice enhances the overall quality of the software and minimizes the chances of issues going unnoticed.

Regression Testing

Regression testing, the process of verifying that new changes do not break existing functionality, relies heavily on change-based testing. When developers make alterations to the codebase, whether it’s for bug fixes or feature enhancements, there is a risk of unintentionally introducing new bugs or disrupting previously functioning parts of the software. Change-based testing targets the areas of the code affected by the recent changes, making regression testing more efficient and precise. This ensures that the software remains stable as it evolves.

Adapting to Agile Practices

CBT aligns with Agile software development practices, which are more adaptable to modern development teams. In Agile methodologies, software is developed incrementally and iteratively. This means that each iteration may involve multiple changes and enhancements. So, CBT helps teams focus their testing efforts on the latest changes, allowing them to validate the progress made during each iteration. This approach supports Agile’s fast-paced development cycles and ensures that the software remains consistent with evolving requirements.

Risk Management

Change-based testing is an essential component of risk management in software development. It facilitates early identification of issues, vulnerabilities, and potential pitfalls associated with recent changes. By concentrating testing on the areas impacted by these changes, development teams can uncover and address risks before they escalate into significant problems. By extension, the likelihood of costly rework, delays, or post-release issues is avoided.

Best Practices for Effective Change-Based Testing

Change-based testing is a valuable approach in software development, but to make the most of it, several best practices should be followed.

Clear Documentation of Changes

Maintain clear and comprehensive records of all changes made to the codebase. Include information such as the purpose of the change, the affected code files, and references to relevant issues or requirements. Clear-cut documentation helps testers and developers understand the context of changes and plan their testing efforts more effectively.

You can utilize version control systems, like Git, to manage and track code changes. Each change should be associated with a commit message that provides a concise and informative summary of the modification.

Prioritize Critical Paths

Assess the impact of changes on the software by identifying critical paths or core functionalities that may be affected. Focus initial testing efforts on these areas to ensure that the most essential parts of the application remain robust and functional. You can adopt risk assessment to help you prioritize testing based on the risk associated with specific changes. High-risk changes, such as security updates or core algorithm modifications, should receive more thorough testing than lower-risk changes, like cosmetic updates.

Automate Regression Testing

Invest in test automation tools that allow for efficient execution of regression tests. Automated test suites can be developed to validate changes quickly and repeatedly, reducing the risk of human error and saving time. In addition, integrate automated testing into your continuous integration (CI) pipeline to ensure that tests are automatically run whenever new changes are committed. Doing this provides rapid feedback to developers and allows them to catch issues early in the development process.

Implement Continuous Integration

Establish a robust CI/CD pipeline. This pipeline should automatically build, test, and deploy your application whenever changes are pushed to the repository. This approach promotes frequent testing and integration of changes, improving the overall stability and reliability of the software.

What follows when you have a CI/CD pipeline is immediate feedback to the developers. It ensures that developers receive immediate feedback on the quality and correctness of their code changes. Fast feedback allows for quick identification and resolution of issues, reducing the chances of defects propagating through the codebase.

Embracing Change-Based Testing for Better Software Development

Implementing change-based testing is a fundamental step toward achieving better software development. The continuous evolution crisscrossing the software industry demands more efficient and adaptable testing methodologies and change-based testing provides a fresh perspective by emphasizing adaptability. This shift from rigid, static testing plans to a dynamic and more responsive approach enables us to keep pace with the ever-changing software landscape and address emerging challenges proactively.

With change-based testing, the chances of early defect detection, enhanced collaboration between development and testing teams, and improved code quality are increased. From a user perspective, change-based testing also helps to develop software solutions that are not only responsive to change but also better suited to meet the evolving needs of users. To succeed in implementing change-based testing, organizations should invest in the right tools and training, foster a culture of continuous learning, and promote cross-functional collaboration. By doing so, they can create a testing environment that thrives on change rather than shying away from it.

Laser Focus Your Testing With Change-Based Testing