Non-functional testing is a type of software testing that focuses on evaluating the non-functional aspects of a software application. Unlike functional testing, which verifies what the system does, non-functional testing checks how the system performs under certain conditions. This type of testing is crucial for ensuring that the software meets certain criteria related to performance, usability, reliability, and more.

1. Performance Testing:

   • Measures the responsiveness, speed, scalability, and stability of a system under a given workload.
   • Types include Load Testing, Stress Testing, and Volume Testing.

2. Usability Testing:

   • Evaluates the user-friendliness of the application.
   • Focuses on the ease of use, user interface, and user experience.

3. Reliability Testing:

   • Assesses the software's ability to perform consistently under specified conditions.
   • Ensures the system can recover from failures and continue to operate.

4. Security Testing:

   • Identifies vulnerabilities, threats, and risks in the software.
   • Ensures that the data and resources are protected from intruders.

5. Compatibility Testing:

   • Checks if the software can run on different devices, operating systems, and browsers.
   • Ensures that the application behaves as expected across various environments.

6. Scalability Testing:

   • Evaluates the software's ability to scale up or down in response to changes in user load.

Let's consider a simple example of performance testing using a web application. The goal is to test how the application performs under a specific number of concurrent users.

1. Define Performance Criteria:

   • Determine acceptable response times, throughput, and resource utilization levels.

2. Create Test Environment:

   • Set up a test environment that mimics the production environment as closely as possible.

3. Design Test Scenarios:

   • Identify key user scenarios and determine the load to be applied.

4. Execute Tests:

   • Use tools like Apache JMeter or LoadRunner to simulate user load and capture performance metrics.

5. Analyze Results:

   • Review the collected data to identify bottlenecks and areas for improvement.

Explanation:

• numThreads: Number of concurrent users.
• rampTime: Time to reach the full load.
• loopCount: Number of times to execute the test.
• HTTPSamplerProxy: Represents an HTTP request to the server.

Exercise: Conduct a basic performance test on a sample web application using Apache JMeter.

1. Setup: Install Apache JMeter on your machine.
2. Create a Test Plan: Design a test plan to simulate 50 users accessing the homepage of a website.
3. Execute the Test: Run the test and collect performance data.
4. Analyze Results: Identify any performance issues and suggest improvements.

Solution:

• Follow the steps outlined in the practical example to set up and execute the test.
• Use JMeter's reporting tools to analyze the results and identify any performance bottlenecks.

• Mistake: Not simulating real-world scenarios.

  • Tip: Ensure that the test scenarios reflect actual user behavior and load patterns.

• Mistake: Ignoring environment differences.

  • Tip: Test in an environment that closely resembles the production setup.

• Mistake: Overlooking data analysis.

  • Tip: Spend adequate time analyzing the results to gain meaningful insights.

Non-functional testing is essential for ensuring that a software application not only functions correctly but also performs well under various conditions. By focusing on aspects like performance, usability, and security, non-functional testing helps deliver a robust and reliable product. In the next section, we will explore Regression Testing, which ensures that new code changes do not adversely affect the existing functionality of the software.