Software Testing Performance & Load Testing 2 — Questions and Answers
Question 1: Which open-source tool is most widely used for load testing and measuring web application performance?
- Selenium
- Apache JMeter (Correct answer)
- Cucumber
- Postman
Correct answer: Apache JMeter
Apache JMeter is the most widely adopted open-source performance testing tool, capable of simulating heavy loads on servers and networks.
Question 2: What does the 95th percentile response time tell you during performance test analysis?
- The average response time across all requests
- The fastest response time recorded in the test
- The response time below which 95% of all requests were completed (Correct answer)
- The response time above which 95% of all requests were completed
Correct answer: The response time below which 95% of all requests were completed
The 95th percentile means 95% of requests completed in that time or less, providing a better picture of user experience than averages, which can be skewed by outliers.
Question 3: What is 'think time' in the context of load test scripting?
- The server-side processing time for handling a request
- The simulated pause a virtual user waits between actions to mimic real behavior (Correct answer)
- The time a performance engineer spends analyzing test results
- The interval between consecutive test script executions
Correct answer: The simulated pause a virtual user waits between actions to mimic real behavior
Think time simulates the natural pause real users take between actions (such as reading a page before clicking), making load scenarios more realistic.
Question 4: Which performance metric represents the percentage of requests that did not complete successfully during a test run?
- Response time
- Throughput
- Error rate (Correct answer)
- Apdex score
Correct answer: Error rate
Error rate is the proportion of failed transactions relative to total transactions, and a rising error rate under load signals system instability.
Question 5: What is the Apdex (Application Performance Index) score designed to measure?
- Server CPU utilization during peak load
- User satisfaction with application response times on a 0-to-1 scale (Correct answer)
- The raw count of concurrent users in a test
- Database query execution time distribution
Correct answer: User satisfaction with application response times on a 0-to-1 scale
Apdex converts response time data into a satisfaction index from 0 (no users satisfied) to 1 (all users satisfied), simplifying communication of performance results.
Question 6: In a performance test configuration, what does 'ramp-up time' refer to?
- The total planned duration of the entire load test
- The recovery period after load is removed from the system
- The period during which virtual users are gradually added to reach the target concurrency (Correct answer)
- The delay between successive iterations of the test script
Correct answer: The period during which virtual users are gradually added to reach the target concurrency
Ramp-up time is the duration over which virtual users are incrementally added, preventing an artificial sudden spike and more closely mimicking organic traffic growth.
Question 7: Which performance testing concept describes the number of users simultaneously active in the system at a given moment?
- Throughput
- Concurrency (Correct answer)
- Latency
- Scalability
Correct answer: Concurrency
Concurrency is the count of users or processes simultaneously interacting with the system, directly influencing resource contention and response time.
Software Testing Performance & Load Testing 2
Which open-source tool is most widely used for load testing and measuring web application performance?