How do you test non-functional features?

1 Define non-functional requirements

Before you can test non-functional features, you need to define the non-functional requirements (NFRs) for your system. NFRs are the criteria that specify how well the system should perform, rather than what it should do. You can use various sources to elicit NFRs, such as business goals, user needs, industry standards, regulatory compliance, and technical constraints. You can also use frameworks, such as ISO 25010, to categorize and prioritize NFRs. You should document NFRs clearly and measurably, using metrics, thresholds, and targets.

2 Choose appropriate testing techniques

Depending on the type and scope of the non-functional features, you can choose different testing techniques to verify and validate them. For instance, Load testing simulates high volumes of user requests or data to measure the system's performance and scalability under stress. Stress testing pushes the system beyond its normal operating limits to identify its breaking point and recovery behavior. Endurance testing examines the system's response to a sustained load over a long period of time to detect memory leaks, resource consumption, and degradation issues. Usability testing evaluates the system's ease of use, learnability, efficiency, and user satisfaction by observing real or representative users performing tasks. Accessibility testing checks the system's compliance with accessibility standards and guidelines, such as WCAG, and its usability by people with disabilities or special needs. Security testing assesses the system's vulnerability to unauthorized access, data breaches, malicious attacks, and other threats. Maintainability testing measures the system's modifiability, testability, reusability, and portability by analyzing its code quality, complexity, documentation, and dependencies.

3 Select suitable testing tools

To test non-functional features effectively and efficiently, you need to select suitable testing tools that support your testing techniques and objectives. There are many testing tools available in the market, both commercial and open source, with varying features and functionalities. For example, JMeter is a popular load testing tool that can generate and simulate various types of user requests and scenarios, while LoadRunner is a comprehensive performance testing tool that can handle complex and large-scale projects. Selenium is a widely used web testing tool that can automate functional and non-functional tests, such as usability, accessibility, and security tests. Axe is a powerful accessibility testing tool that can scan web pages and applications for accessibility issues, while SonarQube is a code quality analysis tool that can measure the maintainability of the system.

4 Plan and execute testing activities

Once you have defined the NFRs, chosen the testing techniques, and selected the testing tools, you can plan and execute your testing activities by following a systematic and structured approach. This involves defining the test objectives, scope, and strategy based on the NFRs and system context. You should also design the test scenarios, cases, and data based on the testing techniques and tools. Additionally, you need to prepare the test environment, infrastructure, and resources based on system specifications and requirements. Afterward, execute the test cases and scenarios using the testing tools and following the test plan. Finally, monitor and control the test process using the testing tools and metrics while reporting any issues or deviations.

5 Analyze and report testing results

The final step of testing non-functional features is to analyze and report the testing results. You should use the testing tools and metrics to evaluate the system's performance, reliability, usability, security, and maintainability, against the NFRs and the expected outcomes. You should also use the testing tools and metrics to identify the root causes, impacts, and risks of any issues or defects. You should document and communicate the testing results, using clear and concise reports, charts, graphs, and dashboards. You should also provide feedback and recommendations for improvement, based on the testing results and analysis.

6 Here’s what else to consider

This is a space to share examples, stories, or insights that don’t fit into any of the previous sections. What else would you like to add?