JMeter & Performance Testing test (Intermediate)

Sample questions

5 sample questions from the JMeter & Performance Testing test, with the answers. Samples are taken out of the live test, so you will not meet these when you sit it.

1. You are working on a JMeter test plan for a REST API that requires handling dynamic authentication tokens returned in JSON responses. Which method should you use to extract and reuse these tokens in subsequent requests?

   1. Use the CSV Data Set Config to store and reuse dynamic tokens from the response in subsequent requests.
   2. Use the HTTP Header Manager to extract the dynamic token from the response and store it in a JMeter variable for reuse in subsequent requests.
   3. Use the Regular Expression Extractor to extract the dynamic token from the response and store it in a JMeter variable for reuse in subsequent requests.
   4. Use the JSON Extractor post-processor to capture the dynamic token from the response and store it in a JMeter variable for reuse in subsequent requests.

   Answer: D. Use the JSON Extractor post-processor to capture the dynamic token from the response and store it in a JMeter variable for reuse in subsequent requests.

   To handle dynamic tokens in a realistic project scenario using JMeter, the JSON Extractor post-processor is the correct choice. It allows you to extract specific values (like tokens) from JSON responses and store them in variables for later use in requests. Other options may not directly address the extraction of dynamic values from JSON responses or may be less effective in this context.

2. Which of the following statements is true regarding the execution of JMeter test plans for real load testing?

   1. JMeter test plans should be run in non-GUI mode for real load testing.
   2. JMeter test plans should be run in GUI mode for real load testing.
   3. JMeter test plans should never be run in non-GUI mode.
   4. JMeter test plans should always be run in GUI mode for accurate results.

   Answer: A. JMeter test plans should be run in non-GUI mode for real load testing.

   Running JMeter test plans in non-GUI mode is recommended for real load testing as it reduces overhead and allows for better performance. The GUI mode is suitable for debugging and planning but not for executing actual load tests due to high resource consumption.

3. Which JMeter listener is best suited for analyzing performance test results and identifying potential bottlenecks or issues in the system under test?

   1. Backend Listener
   2. Summary Report
   3. Aggregate Report
   4. View Results Tree

   Answer: C. Aggregate Report

   The Aggregate Report listener is used to generate a summary of the test results, including metrics such as the average response time, median, 90th percentile, 95th percentile, 99th percentile, throughput, and error percentage. It is the most appropriate listener for analyzing performance test results and identifying potential bottlenecks or issues in the system under test. Other listeners, such as the View Results Tree, are used for debugging and not for generating high-level performance metrics.

4. Which JMeter timer is specifically designed to control the number of requests per minute and shape load during a test?

   1. Constant Timer
   2. Gaussian Random Timer
   3. Uniform Random Timer
   4. Constant Throughput Timer

   Answer: D. Constant Throughput Timer

   The Constant Throughput Timer is the only JMeter timer that directly controls the number of requests per minute, making it ideal for shaping load. Other timers like Constant Timer, Uniform Random Timer, and Gaussian Random Timer only add pauses between requests and do not control the overall throughput rate.

5. Which of the following is a common mistake in simulating concurrent users in JMeter that leads to an artificial spike in load?

   1. Using a ramp-up time of 10 seconds for 100 threads
   2. Using a zero ramp-up time for 100 threads
   3. Using a ramp-up time of 1 minute for 100 threads
   4. Using a ramp-up time of 5 seconds for 100 threads

   Answer: B. Using a zero ramp-up time for 100 threads

   A zero ramp-up time causes all threads to start at the same time, leading to an artificial spike in load that does not reflect real-world user behavior. This can overwhelm the system under test and result in inaccurate performance metrics.