While developing a website, developers have to explore ways to keep it scalable enough to handle unexpected traffic spike and sudden surge in number of transactions. Also, they need to measure the scalability of the web application precisely to prevent sudden and unexpected crashes. Lot of developers and QA testers ask us what is Scalability testing. Scalability testing enables testers to measure the capability of websites to handle increase in user traffic, number of transactions, and data volume. Many testers perform scalability testing independently to check a website’s ability scale up or scale out with varied workload.
At the same time, scalability testing is also performed along with other forms of non-functional testing – performance testing and reliability testing to assess the overall performance of the web applications accurately. The testers can perform scalability testing based on a variety of parameters according to nature of the each application. They can even perform scalability testing as a series of load tests. Also, scalability testing process can be automated using a number of widely used performance testing and load testing tools. But the testers must understand the characteristics that differentiate scalability testing from other forms of non-functional testing.
What is Scalability Testing? Understanding Important Aspects of Scalability Testing
A Form of Non-Functional Testing
As noted earlier, scalability testing is a form of non-functional testing.It is a form of non-functional testing. The scalability testing results help software QA testing professionals to determine readiness of the software application. Also, the results help testers to assess the web application’s user experience and user satisfaction by identifying the amount of time it takes to complete a specific task and respond to the user request.
Different from Load Testing
Many beginners consider scalability testing as an alternative to load testing. Like load testing, scalability testing is also a form of non-functional testing. But the two forms of non-functional testing differ from each other in the category of key focus. QA testers perform Load testing to identify the point under which the website response time falls. Normally, load testing is performed with incremental user loads. On the other hand, scalability testing is performed to measure the performance of a website or web application at various stages from minimum load to maximum load. Here is one of our previous posts on the importance of load testing on SDLC.
The primary objective of scalability testing is to identify the point at which the website stops scaling and find out the reason behind it. The testers perform scalability testing to determine how the website scales as the workload keeps increasing. Also, they focus on measuring the user limit for the website, along with degradation and robustness of the website’s frontend and backend. At the same time, scalability testing also helps testing professionals to assess the website’s user experience under varied workload.
Performed Based on Varied Parameters
Normally, the test strategy for scalability testing differs according to the type and nature of applications. Also, the testers need to perform scalability testing based on varied parameters according to the type of application for testing. For instance, while testing a website, testing professionals perform scalability testing based on the maximum number of probable concurrent users. On the other hand, they use parameters like network usage, CPU usage, or user experience while testing other applications. However, the testers focus on identifying issues related to hardware, software, network, and database while performing scalability testing.
While performing scalability testing, the testers evaluate specific aspects of a software application. Hence, the attributes may differ from one type of software application to another. However, the testers normally test a number of attributes like performance under incremental user load, performance measurement based on concurrent user count, request and response of web server per second, network usage, CPU usage, screen transition, and throughput. Also, they measure requests, hits, and transactions per second as attributes while performing scalability testing.
Important Steps or Stages
The process of scalability testing may differ according to the type of application. But the general scalability testing process consists of a number of stages – defining a process which will be repeated throughout the application lifecycle for execution of scalability tests, selecting scalability criteria, choosing the right load testing tools, configuring hardware and testing requirements, planning load test scenarios, creating load test scenarios, executing scalability tests, evaluating test results, and generating scalability testing reports. Testers have option to combine scalability testing with other forms of non-functional testing like performance testing and reliability testing.
Elaborate Test Plan
The testers cannot streamline scalability testing process without an elaborate test plan. In addition to streamlining scalability testing, the test plan will also help testers to meet precise application requirements and use relevant parameters. However, they must focus on a number of factors to prepare an effective test plan for scalability testing. For instance, the test plan must clearly define the steps to be included in test scripts to determine and evaluate the exact actions to be performed by end users. Likewise, the test plan also needs to determine the runtime data required to interact with the application, and define all fields required in the data if the test scripts are using varying runtime data.
On the whole, QA testers conduct Scalability testing to measure the capability of an application to scale up or scale down based on a number of non-functional parameters or attributes. The testers can further perform scalability testing as a series of load tests. However, they must perform the load tests with varied hardware configurations and software settings. Also, they can integrate scalability testing with other non-functional testing to assess the performance of application more precisely.