What is Non-Functional Testing?
Non-Functional Testing (NFT) is a type of software testing that focuses on evaluating the non-functional aspects of an application, such as performance, reliability, scalability, usability, and security. Unlike functional testing, which verifies what the system does, non-functional testing checks how well the system performs under various conditions.
The main goal of non-functional testing is to ensure that the application meets predefined performance criteria and is ready to handle real-world demands.
Key Objectives of Non-Functional Testing
1. Improve System Quality: Ensure the software is robust, efficient, and user-friendly.
2. Validate Performance Metrics: Confirm the system’s ability to handle high loads, execute tasks quickly, and recover from failures.
3. Ensure Compliance with Standards: Verify that the application adheres to industry regulations and best practices.
4. Minimize Risks: Detect potential bottlenecks, vulnerabilities, or usability issues before deployment.
Characteristics of Non-Functional Testing
1. Focuses on System Behavior: Tests attributes like speed, stability, and reliability rather than functionality.
2. Conducted After Functional Testing: Performed after functional testing confirms that the system works as expected.
3. Simulates Real-World Scenarios: Tests how the application behaves under varying conditions such as high traffic, low bandwidth, or server crashes.
4. Quantitative and Measurable: Results are often expressed in metrics such as response time, throughput, or error rates.
Types of Non-Functional Testing
1. Performance Testing:
- Evaluates how the system performs under normal and peak load conditions.
- Example: Testing an e-commerce website’s response time when 1,000 users browse products simultaneously.
2. Load Testing:
- Measures the system’s ability to handle expected workloads.
- Example: Testing a banking app to ensure it can process 10,000 transactions per minute.
3. Stress Testing:
- Examines how the system behaves under extreme conditions, such as heavy load or limited resources.
- Example: Checking if a video-streaming platform can handle 10x the normal traffic during a live event.
4. Scalability Testing:
- Ensures the system can scale up or down to accommodate changes in workload.
- Example: Testing how a cloud-based CRM system adds resources as more users log in.
5. Security Testing:
- Verifies that the system is protected from unauthorized access and data breaches.
- Example: Checking if sensitive customer data is encrypted during transmission and storage.
6. Usability Testing:
- Ensures the application is user-friendly and easy to navigate.
- Example: Testing whether users can complete a registration process within two minutes.
7. Reliability Testing:
- Confirms that the system performs consistently without failures over a specified time period.
- Example: Testing a hospital’s patient management system for 48 hours to ensure stability.
8. Recovery Testing:
- Evaluates how the system recovers from failures like crashes or hardware issues.
- Example: Testing whether an airline reservation system resumes functionality after a server outage.
9. Compliance Testing:
- Ensures the software adheres to legal and regulatory standards.
- Example: Verifying that a financial application complies with GDPR for data privacy.
10. Localization and Internationalization Testing:
- Tests how well the application supports different languages, regions, and formats.
- Example: Checking whether a news app displays dates in the correct format for the U.S. (MM/DD/YYYY) and Europe (DD/MM/YYYY).
11. Availability Testing:
- Verifies that the system is available as per the agreed service level agreement (SLA).
- Example: Ensuring a SaaS application is available 99.9% of the time.
Tools for Non-Functional Testing
- Performance Testing: Tools: JMeter, LoadRunner, Gatling.
- Security Testing: Tools: OWASP ZAP, Burp Suite, Acunetix.
- Usability Testing: Tools: Crazy Egg, Optimal Workshop.
- Recovery Testing: Tools: Manual testing with simulated failure scenarios.
