Just conducting one type of testing is generally not enough. For example, let’s say you decide to perform unit testing only. However, unit tests only verify business logic. Many other types of tests exist to verify the integration between components, such as integration tests.
But what if you want to measure the maximum performance of your application? Or what if you want to know how the application behaves under extreme stress?
To answer these questions, you can pursue these types of testing:
These types of tests are ideal for answering the above questions. However, the difference between those testing types is subtle.
This article will guide you through each of those testing types. You’ll find out about each type of testing and learn about the differences between them.
Performance testing is an umbrella term for both load and stress testing. Performance testing refers to all testing related to verifying the system’s performance and monitoring how it behaves under stress. Therefore we can say that performance testing is concerned with the following metrics:
Performance testing is often linked to a customer’s functional requirements. Imagine a client who asks to develop a service that handles ticket sales for events. For example, the client expects the application to be able to handle up to 50,000 requests per minute. This is a functional requirement that performance testing helps to validate.
The goal of performance testing is not to find bugs but to find performance bottlenecks. Why is this important? A single performance bottleneck can have a huge impact on the overall application’s performance. Therefore, it’s crucial to conduct performance testing to detect such issues.
In addition, this type of testing also verifies the performance in different environments to make sure the application works well for different setups and operating systems. To give an example, an application might work fine on a Linux server but have performance issues on a Windows server. Performance testing should help you rule out such problems.
In short, the goal of performance testing is to gather insights into the application’s performance and communicate these performance metrics to the stakeholders.
It’s always a good idea to measure the performance of an application. Delivering an application that hasn’t been performance tested is the same as delivering a bike with brakes that haven’t been tested.
Performance testing helps you with the following aspects:
Next, let’s get into the details of load testing.
Load testing specifically tries to identify how the application behaves under expected loads. Therefore, you should first know what load you expect for your application. Once you know this, you can start load testing the application.
Often, load testing includes a scenario where 100 extra requests hit the application every 30 seconds. Next, you’ll want to increase the number of requests up to the expected load for the application. Once the expected load has been reached, most testing engineers prefer to continue hitting the application for a couple more minutes to detect possible memory or CPU issues. These kinds of issues might only pop up after hitting the application for a while and are rarely visible from the beginning.
Moreover, the goal is to gather statistics about important metrics, such as response time, reliability, and stability.
To summarize, load testing is generally concerned with collecting all this data and analyzing it to detect anomalies. The idea of load testing is to create an application that behaves stably under an expected load. You don’t want to see ever-increasing memory usage, as that might indicate you have a memory leak.
Load testing helps you to get a better understanding of the expected load your application can handle. And understanding those limits helps you to reduce the risk of failure.
Let’s say your application can handle 5,000 requests per minute. Because you know this limit, your organization can take precautions to scale the application in case the number of requests per minute gets close to this limit. By taking these precautions, you’re reducing the risk of failure.
In addition, load testing gives you good insights into the memory usage and CPU time of your application. This data is of great value for measuring the stability of your application. Ideally, the memory usage for your application should remain stable when you’re performing load testing.
Last, let’s explore the true meaning of stress testing.
Stress testing helps you detect the breaking point of an application. Also, it allows a testing engineer to find the maximum load an application can handle. In order words, it lets you determine the upper limit of the application.
To give an example, let’s say a certain application programming interface can handle 5,000 simultaneous requests, but it will fail if it has to process more requests for the given setup. This limit is important for companies to know because it allows them to scale their application when needed.
In addition, it’s also a common practice to increase “stress” on the application by closing database connections, removing access to files, or closing network ports. The idea here is to evaluate how the application reacts under such extreme conditions. Therefore, this type of testing is extremely useful when you want to evaluate the robustness of your application.
Stress testing provides the following benefits for you and your organization:
Finally, let’s compare the above three testing types and learn about the differences between performance testing, load testing, and stress testing.
| Key | Stress Testing | Load Testing |
|---|---|---|
| Purpose | Stress testing tests the system’s performance under extreme load. | Load testing tests the system performance for the expected load on the application |
| Threshold | Stress testing is conducted above threshold limits. | Load testing is conducted at threshold limits. |
| Result | Stress testing allows you to evaluate how robust is your application. | Load testing ensures that the system can handle the expected load. |
To finish off, let’s do a quick recap of performance testing, load testing, and stress testing so that you see how these tests are related.
To conclude, don’t neglect performance testing. It’s a great tool for increasing customer satisfaction because you can guarantee that your application works well for them in all usage scenarios. To help you with conducting performance tests, you can use dedicated tools such as Stackify’s Retrace tool . An application monitoring tool gives you insights into memory usage and CPU time. In addition, for Node.js specifically, it can give you insights into the Node.js event loop and how long it’s blocked. An event loop that’s continuously blocked is often a bad sign.
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