A Beginner's Guide to Performance Testing

Performance testing plays a vital role in delivering high-quality software applications that meet user expectations.

A Beginner's Guide to Performance Testing

Imagine this scenario: You've created an awesome application. Developers have systematically created a thorough set of unit tests for all features, the testing team has successfully conducted user acceptance tests, and you have extensively tested your application in a variety of scenarios. You've also run cross-browser testing and tested your application on a variety of mobile devices to ensure that it works smoothly across platforms. Everything looks perfect, and as soon as you launch the app, the users begin to arrive as expected. Suddenly, calamity strikes! The application crashes unexpectedly and refuses to launch. You are surprised by this unexpected finding, after all that exhaustive testing. 

At this point, you realise the value of non-functional tests, especially performance tests.

For this reason, I will focus on performance testing and its importance in this blog post. I will examine the common misconceptions and overlooked aspects that may surface before, during, and following the process of performance testing.

Understanding Performance Testing

In software testing, many new technologies, tools, and test methods have emerged in recent years. Especially in the process from the beginning to the end user, many new test principles and test tools have been developed for the acceptance tests of applications. We briefly define these tests and test approaches as functional tests. 

However, as technology advances and the user base grows, this presents a big challenge to the system’s ability to reliably operate under high loads and long response times. Considering these issues, you can conclude that the system is not operating at its optimal level. But to assess a system's performance, you want more than just conjecture—you also need data. To obtain this data, performance tests, which are non-functional tests, must be conducted in conjunction with functional tests during the application testing process.

If you can not measure it, you can not improve it! icon-test

Performance tests put the system through rigorous tests to assess how well it performs. It is an important and difficult step in the software development process. It's like giving your software a speed, capacity, scalability, and stability check-up instead of just looking for functionality issues! 

In this extensive assessment of a system’s performance, different methods are used to exercise specific aspects of each system. Load testing reveals how the system performs under high-traffic scenarios. Endurance testing measures the system’s durability over extended periods. Scalability testing looks into how well the system can adapt to the changing load required by managing scaling processes, either up or down. Stress testing and volume testing are other examples of these methods. All of these methods provide crucial information that helps improve system performance overall.


Performance Testing Is More Necessary Than Ever


The rapid speed of technical developments and the regular stream of system changes have made performance testing more important than ever. In the rush to push features out to keep up with the rapidly changing technological scene, the emphasis on performance might be unintentionally overlooked. Neglecting performance testing in the face of rapid technological development can lead to unexpected issues, such as application performance bottlenecks and system vulnerabilities. Performance testing can forecast product behaviour and the product's response to user activities under workload in terms of responsiveness and stability when implemented correctly. Through performance testing, you can find out about application performance bottlenecks, system benchmarks to see which ones perform the best, and improvements to the infrastructure.

  • More traffic from more devices: 

As your user base expands, so does the demand for apps. Users can access your app from a variety of locations with varying network settings. Performance testing ensures that your application can handle more users without sacrificing reliability or speed, and it also finds and fixes latency issues, providing a smooth experience to users worldwide.

  • Resource optimization:

Cost-effectiveness depends on the effective use of resources. When resource-intensive areas are identified through performance testing, cloud infrastructure or server deployments can be optimised and cost-effectively reduced.

  • Competitive edge: 

In a competitive market, poor performance may lead customers to look for alternatives. Thorough performance testing helps to maintain a competitive advantage by improving the user experience. Studies show that users tend to abandon a website or app if the page loading time increases. This impatience highlights the critical importance of performance testing, as it directly impacts user retention.

  • User satisfaction and retention:

In today's digital environment, users expect fast response times and easy interaction with software. Users are less tolerant of slow or unreliable applications, and their level of satisfaction has a direct impact on retention. Performance testing is critical for meeting and exceeding user expectations, ensuring that apps continuously offer a pleasant, responsive, and smooth user experience. 

  • Cost saving: 

Performance testing helps in the detection and resolution of problems before they turn into significant ones. In the long term, finding and fixing performance issues through testing can save a lot of money. Fixing performance issues during the development process is usually less expensive than correcting them after the application has been released into production.

Common Misconceptions and Overlooked Aspects



Mistake: Focusing solely on functionality

Despite its criticality, performance testing is sometimes overlooked or ignored during the software development lifecycle. Many project teams spend a great deal of resources testing the functionality of the system but spend little or no time doing performance testing. Teams usually focus on functional tests to ensure that the product is functioning properly while overlooking or paying less attention to performance tests. Overemphasising functional testing may create a false sense of security, as a well-functioning feature does not guarantee excellent performance in real-world scenarios.


Misconception: Performance testing is cheap, easy, and quick

The common misconception that performance testing is quick, easy, and cheap frequently results in important mistakes being made during the software development process. Despite popular opinion to the contrary, successful performance testing needs careful preparation, methodical execution, and an in-depth understanding of the architecture of the application. This is not just a task to be completed on a development checklist; rather, it is an essential procedure that calls for resources, time, and knowledge. The difficulty of data preparation, in particular, emphasises the need to allocate the resources required to precisely simulate the many scenarios under which the system operates while ensuring that the performance testing findings are accurate and reliable. Ignoring this factor might result in a variety of problems, such as subpar user experience and system crashes during heavy usage. It is critical to acknowledge the myth that performance testing is a simple, low-cost operation to guarantee the overall success and dependability of a software product.


Misconception: No need for a production-like environment 

Furthermore, the environment fallacy in performance testing highlights the misconception that testing with an environment different from actual production can produce accurate results. It is best practice to set up dedicated environments for real-time performance testing, ensuring that they are instantiated when needed and destroyed as soon as the tests are completed. Testing under conditions that differ from the production environment frequently produces inaccurate results because it ignores critical performance factors such as operating system settings, hardware configurations, and concurrently running apps. Achieving dependable performance testing demands a meticulous effort to closely match the test and production environments, ensuring that the findings appropriately reflect the system's performance under real-world conditions.

Misconception: Adding more hardware will solve performance issues


It is commonly believed that performance testing is unnecessary because any issues found can be fixed with additional hardware - by adding servers, memory, etc. This belief frequently surfaces when teams experience system slowdowns or performance limitations. It is easy to jump to the conclusion that adding more CPUs, memory, or storage will instantly address the issue at hand rather than thoroughly analysing and improving the current system. Upgrading hardware may help temporarily, but it will not solve underlying software or architectural issues that are the root of the performance issues. Effective performance improvements require an approach that is deeper than just adding more hardware, one that takes into account software architecture, bottleneck identification, code optimisation, and behaviour analysis of the system.

Mistake: Scenarios that do not represent  real user behaviour

A frequently overlooked aspect of performance testing is its inability to simulate real-world scenarios accurately. Understanding and recognizing your customers' actions is critical while doing performance testing. Each user exhibits their own behaviours, interacts differently, and has different requests. Tailoring performance tests to imitate different user personas and their distinct behaviours helps you see how the system will perform under various usage patterns. Performance testing becomes more comprehensive and realistic by modelling scenarios that match actual user behaviours, such as variable traffic loads, transaction types, or geographic locations.

QA Engineer walks into a bar. Orders a beer. Orders 0 beers. Orders 999999999 beers. Orders a lizard. Orders -1 beer. Orders a sfdeljknesv. But the First customer comes in and asks where the toilet is. The bar bursts into flames and the customer kills everyone.



In this blog post, I have talked about performance testing in general terms and the misconceptions in this process. Performance testing plays a vital role in delivering high-quality software applications that meet user expectations. By evaluating performance characteristics, identifying bottlenecks, and optimising system components, performance testing ensures an application's responsiveness, scalability, stability, and reliability.

Elif Ozcan

Software Test Consultant @kloia