Introduction
In software testing, it is not enough to check whether features work correctly. We must also verify how well the system performs under different conditions.
What is Non-Functional Testing?
Non-functional testing verifies system performance, reliability, scalability, usability, and security. It focuses on how the system behaves rather than what it does.
For example, even if login works correctly, does it respond within 2 seconds when 10,000 users log in at the same time?
Functional vs Non-Functional Testing
- Functional Testing: Checks what the system does.
- Non-Functional Testing: Checks how well the system performs.
Types of Non-Functional Testing
- Performance Testing
- Load Testing
- Stress Testing
- Scalability Testing
- Security Testing
- Usability Testing
- Compatibility Testing
- Reliability Testing
Non-Functional Testing Approach
- Identify performance requirements
- Select appropriate tools
- Prepare test environment
- Design test scenarios
- Execute tests
- Analyze results
Real-World Examples
Example 1: Performance Testing
- Website should load within 3 seconds
- API response time under 500ms
Example 2: Security Testing
- Prevent SQL Injection
- Ensure password encryption
Example 3: Usability Testing
- Buttons clearly visible
- Navigation easy to understand
Advantages of Non-Functional Testing
- Improves system performance
- Enhances security
- Ensures system stability
- Improves user satisfaction
Non-Functional Testing Interview Questions
What is non-functional testing?
It verifies system performance, scalability, reliability and security.
Is load testing part of non-functional testing?
Yes, load testing is a type of performance testing.
Why is non-functional testing important?
Because a system may work functionally but fail under heavy traffic.
Frequently Asked Questions
Can non-functional testing be automated?
Yes. Performance and security testing often use automation tools.
Which tools are used?
JMeter, LoadRunner, OWASP ZAP and others.