Enhance Your Regression Testing: Key Strategies for Success

Among the various forms of software testing, regression testing often stands out as the most misunderstood and misapplied. So, let's clarify what regression testing really is. At its core, regression testing aims to detect if previously functioning aspects of the software have stopped working correctly after changes were made. It’s about ensuring that new modifications haven’t unintentionally compromised existing functionality.

This article covers the main principles of regression testing, including multiple practical ways to enhance its efficiency, as detailed in the article “9 Ways to Boost Your Regression Testing” by Randall W. Rice.

The Scope and Depth of Regression Testing

If we fully understood the potential impact of a change, regression testing wouldn't be necessary. Since almost any change can potentially impact other system elements, the scope of regression testing can be extensive. The question then becomes: “If anything could be impacted by a change, how much regression testing should we perform?”

The scope can be extensive, including impacts from operating systems, databases, and even server upgrades. We must balance this with risk, resources, and tools. High-risk applications may require testing all cases, while lower-risk scenarios might involve a smaller portion of regression tests.

Core Principles of Regression Testing

Understanding the fundamental principles of regression testing makes the practice more logical and easier to implement. Let's explore these essential principles

1. Passed Before, Not Now: The heart of why regression testing is crucial, as every software change requires retesting due to potential impacts on previously validated functions. Testing captures a moment in time, and what passed before may not pass again.

1. Build Regression Suite Over Time: Start with basic regression tests and slowly add more over time. This method helps manage the risk of missing important tests while gradually developing a thorough regression suite. Another possible practice is to identify good regression tests as functional tests are being made. 

1. Ongoing Maintenance: Regression tests must evolve alongside system changes to stay relevant. Maintaining clear traceability between tests and their requirements/user stories is crucial for adapting to evolving software.

1. Complexity is the Enemy: Complex systems increase the difficulty to define and perform tests, as well as the maintenance efforts. High complexity in systems can occur when there are high levels of integrations between software modules and other components, or even from inner coding practices.

Effective Ways to Boost Your Regression Testing

Automate Your Regression Testing

Automation is crucial in regression testing because even minor deviations from previous correct tests can signal defects. Manual testing is much more prone to human error and exposed to inaccuracies. It's challenging to maintain precision and avoid missing subtle differences when manually conducting extensive regressions. Automation tools ensure exactness and efficiency, handling thousands of tests and comparisons effortlessly. They mitigate the fatigue and oversight that can occur during manual testing, making them critical for sustained and thorough regression testing efforts.

Focus on Essential Functionality

In regression testing, even the most simple tests that look trivial, can be highly important. Take a word processing software, as an instance: Features like spell-checking and document merging are complex but secondary to fundamental functions like opening, creating, saving, and printing documents. If these core functions fail, even advanced features become inaccessible. So when it comes to regression testing, do not underestimate essential, “simple” functionalities. 

Build a Restorable Test Data Source

Ensuring repeatable regression testing hinges on managing test data effectively. While basic test data can be created manually, relying on spreadsheets can lead to reliability issues. For more complex scenarios, leveraging a comprehensive, modern test management platform becomes essential. These tools enable enhanced control and organization of all testing data, including traceability between tests, requirements, and defects, ensuring consistency and reliability in regression testing efforts.

In the image below, we can see the basic process for regression testing, which includes repeatable and restorable test data.

Control the Scope of Regression Testing

Handling the scope of regression testing can seem overwhelming at first, given the many functions and time involved, even with automation. Start by identifying essential targets for testing early on and expand gradually. Beginning with a smaller set, like 50 tests, allows for refining processes without a large initial commitment. Learning from these tests early helps adjust and improve over time. Tailoring the scope based on capabilities, time, tools, risk, and resources ensures effective regression testing that adapts to project needs.

Prioritize Testing Based on Risk and Criticality

Like every type of testing, you should prioritize functions based on their risk of failure and criticality. Risk considers the likelihood and impact of potential failures, while criticality assesses the importance of specific functions, processes, or systems. Remember the word processing application example? Opening a document is critical for usability, even though it may pose a moderate risk of failure.

Conversely, functions like mail merge might have higher risk but lower criticality and they may not affect overall usability significantly. Understanding these distinctions helps focus regression testing efforts on areas that most impact application reliability and user experience.

Want to Explore More? 

Interested in discovering more ways to enhance your regression testing? Read the full “9 Ways to Boost Your Regression Testing” article now for additional strategies and insights that can help optimize your testing efforts.