Time is money
This is more true than ever in today’s business world and more so on the World Wide Web than in real world. That is why it is important to ensure that systems work smoothly, regardless of their duration and usage. Problem-free, that means fast and reliable in this context, because long waiting times cost a company a lot of money – internally and externally.
A slow ecommerce site (as well as e-banking and many other web applications and sites) means unhappy clients. Big players cannot risk clients leaving their site. A slow website response has a significant negative impact on sales. So that a smooth work with a system is guaranteed, it is necessary to limit waiting times (searching, checkout process, browsing, …) for users to a minimum. That is where performance test comes in – checking speed with which a system works. If the result is not satisfactory, it is up to the company to make performance improvements.
The tested system should run optimally and efficiently with all its components. This is exactly what a load and performance test should prove or find out.
Types of load tests and load profiles/ workloads
To find out which load profile or workload should be used, we first define what goal is being sought. Depending on the requirement profile, the test can check the system for different scenarios.
Terms are used differently depending on the company or literature. At the core, however, often the same thing is meant.
So there is the stress test, in this, the load, starting from a small starting value, steadily increased until the system has errors and the load is no longer able to withstand. While the load increases linearly, the performance usually flattens out at some point. We are looking for the moment when the response power drops exponentially as the workload increases. At this point, the maximum capacity of the system is reached.
The continuous load test, on the other hand, checks stability, resource requirements and response time by running for a longer period of time (12 hours to several days). Memory leaks (memory-leaking memory leaks) are also easily identifiable here.
The scalability test is used to find out how intensive a system can be used and whether it “scales” well with more hardware. Say, if with more hardware also more work load with still good response times is processed.
The performance test is often used as a generic term for test types that deal with time behavior. According to ISTQB the correct term would be performance test or efficiency test, but this is rarely used in practice. According to ISTQB, the load test is a kind of performance test.
In the real world of software testing, independent of curriculum, “load and performance testing” is by far the most widely used generic term for performance test types. In companies often quite pragmatic with the above mentioned abbreviations “LPT” or “LuP”.
According to ISO/ IEC 25010:2011, efficiency is also one of the six superior quality features, including the performance test.
In addition, a load test can be set up at various interfaces, via GUI (eg. TruClient), via API (HTTP, web services, REST) or, for example, via SQL directly in the database.