What is Non-Functional Testing, Types with Example

Non-Functional Testing involves assessing aspects of a software application beyond its basic functionalities. This type of testing evaluates non-functional parameters like performance, usability, reliability, and other critical attributes that can significantly impact the user experience. Unlike functional testing, which focuses on specific features and behaviors, non-functional testing examines the system’s overall readiness in these non-functional areas, which are essential for user satisfaction.

For instance, an illustrative example of non-functional testing involves determining the system’s capacity to handle concurrent logins. This type of testing is essential for ensuring that a software application can support the expected number of users simultaneously without any performance degradation.

Both functional and non-functional testing play vital roles in software quality assurance, with non-functional testing being particularly crucial for delivering a well-rounded, high-quality user experience.

Objectives of Non-functional testing

The objectives of Non-Functional Testing are to evaluate and ensure that a software application meets specific non-functional requirements and performance expectations. Here are the key objectives of Non-Functional Testing:

• Performance Testing

Ensure the system performs efficiently under various conditions, such as different levels of user loads, data volumes, and transaction rates.

• Load Testing

Determine how the software handles expected and peak loads. It assesses system behavior under high traffic or usage conditions.

• Stress Testing

Evaluate the system’s ability to handle extreme loads, beyond normal operational limits, and assess how it recovers from such stressful situations.

• Scalability Testing

Determine the system’s ability to scale up or down to accommodate changes in user base or data volume, while maintaining performance.

• Reliability Testing

Verify that the software can perform consistently over an extended period without failures or breakdowns.

• Availability Testing

Ensure that the system is available and accessible to users as per defined service level agreements (SLAs).

• Usability Testing

Evaluate the user-friendliness and overall user experience of the software, including ease of navigation, responsiveness, and intuitiveness.

• Compatibility Testing

Confirm that the software functions correctly across different platforms, browsers, operating systems, and devices.

• Security Testing

Identify vulnerabilities, assess security measures, and ensure the software is resilient against potential threats and attacks.

• Maintainability Testing

Assess how easily the software can be maintained, updated, and extended over time.

• Portability Testing

Verify that the software can be transferred or replicated across different environments, including various platforms and configurations.

• Recovery Testing

Evaluate the system’s ability to recover from failures, such as crashes or hardware malfunctions, and ensure data integrity.

• Compliance Testing

Ensure that the software adheres to industry-specific standards, regulations, and compliance requirements.

• Documentation Testing

Review and validate all associated documentation, including user manuals, technical specifications, and installation guides.

• Efficiency Testing

Assess the system’s resource utilization, such as CPU, memory, and disk usage, to ensure optimal performance.

Characteristics of Non–functional testing

Non-functional testing has specific characteristics that distinguish it from functional testing.

• Performance-Centric

Non-functional testing primarily focuses on evaluating the performance attributes of a system, including speed, scalability, and responsiveness.

• Not Feature-Specific

Unlike functional testing, which targets specific features and functionalities, non-functional testing assesses broader aspects like reliability, usability, and security.

• Assesses Quality Attributes

It aims to validate various quality attributes of the software, including performance, usability, reliability, maintainability, and security.

• Concerned with User Experience

Non-functional testing is crucial for ensuring a positive user experience by evaluating factors like usability, responsiveness, and accessibility.

• Stressful and Extreme Conditions

Non-functional testing involves subjecting the system to extreme conditions, such as high loads, data volumes, or stress levels, to assess its resilience and recovery capabilities.

• Not Easily Automated

Some types of non-functional testing, such as usability testing and security testing, may be challenging to automate and often require manual intervention.

• Influences System Architecture

Non-functional testing outcomes can influence design decisions related to system architecture, resource allocation, and infrastructure setup.

• Impacts User Satisfaction

The results of non-functional testing significantly impact user satisfaction and overall perception of the software’s performance and quality.

• Covers a Broad Range of Areas

Non-functional testing encompasses various areas, including performance, reliability, usability, compatibility, security, and more.

• Not Binary Pass/Fail

Non-functional testing often provides quantitative results, allowing for degrees of compliance rather than a simple pass/fail status.

• Incorporates User Expectations

Non-functional testing is aligned with user expectations and requirements, ensuring that the software meets their non-functional needs.

• Involves Specialized Tools and Techniques

Some types of non-functional testing, such as performance testing or security testing, require specialized tools and techniques to conduct effectively.

• Aids in Risk Mitigation

Non-functional testing helps identify and mitigate risks related to performance bottlenecks, security vulnerabilities, and other quality attributes.

• Continuous Process

Non-functional testing is not a one-time activity; it needs to be performed regularly, especially when there are significant changes or updates to the system.

Non-functional testing Parameters

Non-functional testing evaluates various parameters or attributes of a software application that are not related to specific functionalities. These parameters are essential for assessing the overall performance, usability, reliability, and other critical aspects of the software.

1. Performance:
   • Response Time: Measures how quickly the system responds to user actions or requests.
   • Throughput: Evaluates the number of transactions or operations the system can handle per unit of time.
   • Scalability: Assesses the system’s ability to handle an increasing workload without significant performance degradation.
2. Reliability:
   • Availability: Measures the percentage of time the system is available for use without any disruptions or downtime.
   • Fault Tolerance: Determines the system’s ability to continue functioning in the presence of faults or failures.
3. Usability:
   • User Interface (UI) Responsiveness: Assesses the responsiveness and smoothness of user interactions with the application’s interface.
   • User Experience (UX): Evaluates the overall user experience, including ease of navigation, intuitiveness, and user satisfaction.
4. Security:
   • Authentication: Validates the effectiveness of the system’s authentication mechanisms in protecting user accounts.
   • Authorization: Ensures that users have appropriate access rights and permissions based on their roles.
   • Data Encryption: Verifies that sensitive information is securely encrypted during transmission and storage.
5. Compatibility:
   • Browser Compatibility: Tests whether the application functions correctly across different web browsers.
   • Operating System Compatibility: Ensures the application is compatible with various operating systems.
6. Scalability and Load Handling:
   • Load Capacity: Assesses the maximum load the system can handle before experiencing performance degradation.
   • Concurrent User Handling: Determines how many users the system can support simultaneously without a noticeable drop in performance.
7. Maintainability:
   • Code Maintainability: Evaluates how easily the codebase can be updated, extended, and maintained over time.
   • Documentation Quality: Assesses the clarity and comprehensiveness of system documentation for future maintenance.
8. Portability:
   • Platform Portability: Checks whether the application can be run on different platforms and environments.
   • Database Portability: Ensures compatibility with various database systems.
9. Compliance and Legal Requirements:
   • Ensures that the application adheres to industry-specific standards, regulations, and legal requirements.
10. Efficiency:
    • Resource Utilization: Measures the efficient use of system resources, such as CPU, memory, and disk space.
11. Recovery and Resilience:
    • Recovery Time: Evaluates how quickly the system can recover after a failure or disruption.
    • Data Integrity: Ensures that data remains intact and consistent even after unexpected events.
12. Documentation:
    • User Documentation: Assesses the quality and comprehensiveness of user manuals, guides, and help documentation.

Non-Functional Testing Types

Non-functional testing encompasses various types, each focusing on specific aspects of software performance, usability, reliability, and more.

1. Performance Testing:
   • Load Testing: Evaluates the system’s performance under expected load conditions to ensure it can handle the anticipated number of users.
   • Stress Testing: Assesses the system’s behavior under extreme conditions or beyond normal operational limits to identify breaking points.
   • Capacity Testing: Determines the maximum capacity or number of users the system can handle before performance degrades.
   • Volume Testing: Checks the system’s ability to manage large volumes of data without performance degradation.
2. Usability Testing:
   • Assesses the user-friendliness and overall user experience of the software, including ease of navigation, user flows, and UI responsiveness.
3. Reliability Testing:
   • Availability Testing: Ensures that the system is available and accessible to users as per defined service level agreements (SLAs).
   • Robustness Testing: Assesses the system’s ability to handle unexpected inputs or situations without crashing or failing.
4. Compatibility Testing:
   • Browser Compatibility Testing: Checks whether the application functions correctly across different web browsers.
   • Operating System Compatibility Testing: Ensures the application is compatible with various operating systems.
   • Device Compatibility Testing: Verifies that the application works as intended on different devices, such as desktops, tablets, and mobile phones.
5. Security Testing:
   • Authentication Testing: Evaluates the effectiveness of the system’s authentication mechanisms in protecting user accounts.
   • Authorization Testing: Ensures that users have appropriate access rights and permissions based on their roles.
   • Penetration Testing: Simulates real-world attacks to identify vulnerabilities and weaknesses in the system’s security.
6. Maintainability Testing:
   • Code Maintainability Testing: Assesses how easily the codebase can be updated, extended, and maintained over time.
   • Documentation Testing: Reviews and validates all associated documentation, including user manuals, technical specifications, and installation guides.
7. Portability Testing:
   • Platform Portability Testing: Checks whether the application can be run on different platforms and environments.
   • Database Portability Testing: Ensures compatibility with various database systems.
8. Scalability Testing:
   • Assesses the system’s ability to scale up or down to accommodate changes in user base or data volume, while maintaining performance.
9. Recovery Testing:
   • Evaluates the system’s ability to recover from failures, such as crashes or hardware malfunctions, and ensure data integrity.
10. Efficiency Testing:
    • Measures the system’s resource utilization, such as CPU, memory, and disk usage, to ensure optimal performance.
11. Documentation Testing:
    • Reviews and validates all associated documentation, including user manuals, technical specifications, and installation guides.
12. Compliance Testing:
    • Ensures that the software adheres to industry-specific standards, regulations, and compliance requirements.

Example Test Cases Non-Functional Testing

1. Performance Testing:

• Load Testing:
  • Verify that the system can handle 1000 concurrent users without significant performance degradation.
  • Measure response times for critical transactions under load conditions.
• Stress Testing:
  • Apply a load of 150% of the system’s capacity and monitor how it behaves under extreme conditions.
• Capacity Testing:
  • Determine the maximum number of users the system can handle before performance degrades.
• Volume Testing:
  • Test the system with a database size that is 3 times the anticipated production size.

2. Usability Testing:

• User Interface (UI) Responsiveness:
  • Verify that the UI responds within 2 seconds to user interactions.
• Navigation Testing:
  • Ensure that users can navigate through the application intuitively.
• Accessibility Testing:
  • Check that the application is accessible to users with disabilities using screen readers or keyboard navigation.

3. Reliability Testing:

• Availability Testing:
  • Verify that the system is available 99.9% of the time, as per SLA.
• Robustness Testing:
  • Test the system’s behavior when provided with unexpected or invalid inputs.

4. Compatibility Testing:

• Browser Compatibility Testing:
  • Verify that the application functions correctly on Chrome, Firefox, and Safari browsers.
• Operating System Compatibility Testing:
  • Test the application on Windows 10, macOS, and Linux operating systems.

5. Security Testing:

• Authentication Testing:
  • Ensure that only authorized users can access sensitive areas of the application.
• Authorization Testing:
  • Verify that users have the appropriate access rights based on their roles.
• Penetration Testing:
  • Conduct simulated attacks to identify vulnerabilities in the application’s security.

6. Maintainability Testing:

• Code Maintainability Testing:
  • Assess how easily code can be updated and extended without introducing new defects.
• Documentation Testing:
  • Validate the quality and completeness of user manuals, technical specifications, and installation guides.

7. Portability Testing:

• Platform Portability Testing:
  • Verify that the application runs on Windows, macOS, and Linux platforms.
• Database Portability Testing:
  • Ensure compatibility with MySQL, PostgreSQL, and Oracle databases.

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