Performance Testing: An Overview

Performance testing is a crucial aspect of software development that ensures the quality and reliability of your applications. In this article, we will discuss the definition and scope of performance testing, its benefits and challenges, and the best practices and tools for performance testing along with an example of JMeter.

What is Performance Testing?

Performance testing is a type of testing that measures the performance of a system. It is a non-functional testing technique that determines how the stability, speed, scalability, and responsiveness of an application holds up under a given workload.

Performance testing can help answer questions like:

1. How fast does a website load when 1000 users are accessing it at the same time?
2. How much memory does an application use when it is processing 10,000 records?
3. How stable is a system when it is running for 24 hours continuously?

Why Do We Need Performance Testing?

There are many benefits to performance testing. It can help identify bottlenecks and other issues that may affect the user experience. It can also help ensure that your applications can handle high levels of traffic and usage.

There are many performance testing tools available in the market, including JMeter, Load Ninja, and WebLoad. Our favorite Postman is also introducing its own performance testing tool.

Steps to Perform Performance Testing

The steps required to perform performance testing are:

1. Identify the testing environment: This involves identifying the hardware, software, network configurations, and tools available for the testing process. It also involves understanding the production environment and the user expectations for the software performance.
2. Identify the performance metrics: This involves defining the criteria for measuring the performance of the software, such as response time, throughput, resource utilization, error rate, etc. It also involves setting the performance goals and thresholds for each metric.
3. Plan and design performance tests: This involves creating a test plan that describes the test objectives, scope, strategy, scenarios, workload, data, risks, and schedule. It also involves designing the test scripts that simulate the user actions and transactions on the software.
4. Configure the test environment and distribute the load: This involves setting up and verifying the test environment with the required hardware, software, network, and tools. It also involves distributing the load among different machines or servers to generate realistic user load.
5. Implement test design and run the tests: This involves executing the test scripts according to the test plan and monitoring the system performance during the test execution. It also involves collecting and storing the test results for analysis.
6. Analyze, tune and retest: This involves analyzing the test results to identify the performance issues and bottlenecks in the software. It also involves tuning or optimizing the system configuration, code or design to improve performance. It also involves retesting the software to verify if the performance issues are resolved or not.

JMeter Demo

In this section, we will provide a demo of using JMeter for performance testing. JMeter is a popular open-source tool for performance testing that can simulate a heavy load on a server, network or object to test its strength or to analyze overall performance under different load types.

After you download JMeter from the official page, extract the zip and head over to /bin directory. It's important to note that you must have java installed on your system to use JMeter as this is a 100% pure Java application.

Open the jmeter.bat file. Note that JMeter comes in two modes. The GUI mode should only be used for test creation and debugging. Observe the interface. Notice a Test Plan on the left section of the screen, a test plan contains all the elements of a test. Right click on the Test Plan, Add -> Threads (Users) -> Thread Group, and add a thread group.

A Thread Group defines a pool of users that will execute a particular test case against your server. In the Thread Group GUI, you can control the number of users simulated (number of threads), the ramp up time (how long it takes to start all the threads), the number of times to perform the test, and optionally, a start and stop time for the test.

Fill in some values for the Thread Group. These values determine the frequency and the intensity for the test that would be run. Here is what some of the Attributes mean.

• Number of Threads - Number of users to simulate.
• Ramp-up Period - How long JMeter should take to get all the threads started. If there are 10 threads and a ramp-up time of 100 seconds, then each thread will begin 10 seconds after the previous thread started, for a total time of 100 seconds to get the test fully up to speed.

To read more about all the attributes please head over to the official documentation.

Next we tell JMeter about the API that we want to test. For the sake of this article, let's use a dummy api provided by Dummy API'S. For this we need to add a Add -> Sampler -> Http request to our Thread group created above and then populate all the values.

Next fill in the API details. For this article we can use the a sample api as is given below.

Now upon running the test, JMeter will hit the our API as per the configuration defined in the thread group. However we won't be able to see the results yet. To view the results let's add a listener to our HTTP Request. There are many different listeners available in JMeter. For the purpose of this article, let's add a View Results in Table listener.

Voila! We are done. Now we just need to run our test. Click on the Green triangle on the toolbar and observe the results in the View Results in Table listener.

We can see that we got success (200) for all the five users (threads) that we created in our thread group. Now we can change the Thread Group configuration and see the corresponding results.

Conclusion

In conclusion, performance testing is a crucial aspect of software development that ensures the quality and reliability of your applications. By following the steps outlined in this article and using tools like JMeter, you can effectively measure the performance of your system and identify any issues or bottlenecks that may affect the user experience. Performance testing can help ensure that your applications can handle high levels of traffic and usage, providing a smooth and seamless experience for your users.