Test Types
Non-Functional Testing
Testing qualities of the system like performance, usability, security, and reliability — not specific features.
Full definition
Non-functional testing evaluates the quality attributes of a system — how well it works, rather than what it does. While functional testing checks 'does the login work?', non-functional testing asks 'how fast is the login? how secure? how usable?'
Types of non-functional testing:
- Performance testing: Speed, throughput, scalability
- Security testing: Vulnerability identification
- Usability testing: Ease of use
- Accessibility testing: Disability accommodation
- Reliability testing: Consistency over time
- Compatibility testing: Works across platforms
- Localization testing: Works in different languages/regions
- Recovery testing: Behavior after failures
Non-functional requirements are often overlooked but cause the most user frustration. A feature that works perfectly but takes 10 seconds to load is practically broken.
ISO 25010 quality model defines key quality characteristics: functional suitability, performance efficiency, compatibility, usability, reliability, security, maintainability, and portability.