How load testing, stress testing, and performance testing differ from one another

Software testing is an essential part of the SDLC involving software development and deployment as well. The reason for testing a software is to ensure it operates as per the required parameters and is shorn of any bug, which could otherwise impact its functioning. Moreover, any comprehensive testing of the software ensures the end-user is fully satisfied with its performance. It also allows testers to accurately check the performance of the software and find its optimum performance range. Broadly speaking, there are mainly three types of performance checks that testers can use on any software, namely, load testing, stress testing, and performance testing.

Load testing: This type of testing is done to figure out the number of users a software system can handle effortlessly. Here, various components of the software system are checked individually to find their performance in different scenarios. For example, you can put loads of users or products to check the performance of the homepage or checkout page of an e-commerce portal. There are many automated tools available in the market like WAPT or LoadRunner to execute application load testing.

The main goal of load testing is to find out the largest job a software system can handle. During load testing, various attributes such as server throughput, the highest performance level, response time under different loads, the number of users the application can handle, the adequacy of H/W environment, and so on are tested.

The testers use this type of testing to figure out load-balancing problems, bandwidth issues, memory leaks, memory management, and the upper limit of all the components of an application. One example of a load testing is checking the mail server of a system that has a huge number of concurrent users. This type of testing tells about the number of concurrent users the software can support and whether there is any need to scale the software to ensure its accessibility without adversely affecting its performance.

Stress testing: Stress testing allows testers to ascertain the stability as well as the robustness of the system. It is primarily non-functional testing that uses auto-generated models to simulate various hypothetical situations.

The main goal of this testing is to find out how the system will behave when it faces extreme loads and how to recover should there be any failure. The QA experts use this test to ensure the server does not crash if the system is subjected to a sudden high load. At the same time, it maintains the stability of the system and optimizes its response time.

In stress testing, the quantum of the load is put above the threshold of a breakpoint. One example of stress testing is to shut down a system and then restart the ports of a larger network to find out whether the system has saved the data before crashing.

Performance Testing: Performance testing figures out the speed of the computer as well as the network on which the software or an application will run.

This type of testing is done mainly to validate the performance of all the components of a system. Here, the software is put under different load scenarios and checked for the performance of its components for different parameters. This testing is very important as it sets the performance benchmark for any software. Moreover, here, the features of software like resource usage and reliability are checked.

Unlike in load and stress testing, the load limit in performance testing is kept below as well as above the breakpoint. This is done to find out the range within which the software can perform optimally.

Performance application testing can be executed by checking the HTTP connections, the suitable response time, and so on. It validates the optimum performance of an application and checks whether it conforms to the performance needs of the business. It also allows testers to find any performance issues, so that they (along with the developers) can analyse them thoroughly and find an appropriate solution. It also validates whether the hardware of the system is adequate to handle the high load.

Conclusion: The testing of software prior to its deployment in the market is essential to ensure it performs flawlessly even when subjected to severe loads. In a dynamically changing the market with shifting customer preferences, performance, load and stress testing has become important to validate the robustness and consistency of software.