The importance of Load Testing

The latest software applications need to be compatible across a plethora of digital platforms. These include devices, operating systems, browsers, frameworks, third-party APIs, and networks. However, the success of such applications can only be ensured if they are able to function seamlessly across the above-mentioned digital elements or channels for peak load conditions. In other words, the applications should perform accurately and without any issues (latency, downtime, etc) should they be subjected to specific load patterns. However, to ensure the software performs to its optimum capacity when faced with extreme loads, it should undergo load testing.

What is load testing?

As non-functional testing, it is carried out to find out the behavior of a software application under specific load threshold. A software application load testing helps to determine a system’s behavior during normal and peak traffic conditions. For example, during Black Friday sales in the West, people throng retail or eCommerce stores in droves. And unless these systems have undergone load testing, they can get overwhelmed leading to system latency, downtime, or worse, crashes. This type of application performance testing is meant to check an application’s performance in the event of a large number of users trying to access it at the same time.

What does application load testing tell us?

The following outcomes can be determined by subjecting an application to load testing.

·       Identify if the hosting infrastructure is sufficient to run the application.

·       Find if the application is able to perform to its optimum when subjected to its peak user load.

·       Verify the number of simultaneous users the application can handle. Also, evaluate the hardware configuration, network capacity, and other considerations the application may require to function optimally.

·       Identify the specific element in the application that is causing the deterioration in performance. For example, in the event of an increase in user count, the testing would throw light on the quantum of memory and processor usage, and response time for network bandwidth.

Benefits of load performance testing

To ensure software applications perform to their optimum when maximum number of users try to access them at the same time, they should undergo rigorous load testing. The benefits to accrue from such a type of performance testing include:

Stimulation of real-time user scenarios: It is important to know how an application, website, or API shall behave when accessed by a large number of users at a given point in time. It is needed to prevent situations like system latency, downtime, or crashes, which have the potential to mar customer experience and confidence. Simulating real user scenarios can help in identifying bugs or understanding bottlenecks that may impact the application when put to real use.

Measurement of the quality of product or service: Application performance testing measures the quality of a product or service as per the user behavior. Testers using tools like LoadRunner, Blitz, BlazeMeter, CloudTest, and Apache JMeter evaluate an app or website’s performance under actual load conditions. Also, the testing exercise monitors the throughput of servers, memory, CPU, and other hardware elements when subjected to extreme load thresholds.

Analysis of key performance parameters: Testers, through application load testing, can identify a slew of performance parameters. These include throughput, response time per transaction, delay in network between server response and client request, or design issues. Further, configuration issues like database server, application server, web server, memory limitation, and CPU maximization are identified.

Improved scalability: This type of performance testing helps testers to find out the actual quantum of load that an application, web portal, or server can support. The information can be of great help when developers need to scale up the infrastructure as per the changing business demand. Besides, in order to preempt special load scenarios like Black Friday, music festivals, or sporting events witnessing a surge in traffic, testers can perform special load testing.

Prevention of application failure: Any application may contain a hidden glitch, which, if not identified and mitigated in time, can lead to its failure. Such failures can manifest themselves when the load is beyond the capacity of the application to handle. This is where load testing can help by detecting such issues early on in the SDLC. If not, such failures can incur huge costs for organizations and impact their brands adversely.

Conclusion

Load testing can help an organization to evaluate the capacity of an application or website. It ensures user satisfaction in the case of a surge in traffic and renders superior performance for the software. This type of testing should be made a part of the usual QA process to preempt software failure.

Building the right Performance Testing strategy

In our digitally-connected world where companies are churning out umpteen number of products or services to be accessed over digital devices, performance becomes a sticky issue. The word ‘sticky’ has been used deliberately as the performance of a product or service depends on a host of factors. And delivering a glitch-proof product is no guarantee of its smooth performance. In fact, factors like responsiveness, network bandwidth, and others can deal a body blow to the performance of an application. Just think of an airlines portal catering to thousands of transactions every second. If the portal does not follow a robust performance testing strategy and selects a threshold for load, it is likely to crash midway or show latency. This can adversely impact the user experience.

What is performance testing?

It is a form of software testing where the application under test needs to be checked for its load handling capacity. The load performance testing process determines the stability, speed, throughput, and responsiveness of an application or system when working under a load. It is a non-functional testing that comprises various tests such as load test, capacity test, scalability test, soak/endurance test, volume test, and spike test.

To build the right performance testing strategy, one must be aware of the associated challenges. These include

·         Testing the software under realistic scenarios

·         Picking the right tool to simulate real users

·         Lack of test data

·         Limited test coverage area

·         Poor scalability not allowing the handling of concurrent tasks

·         Poor network configuration

·         Insufficient hardware resources like low performing CPUs

·         Insufficient capacity to handle the workload

The performance testing methodology should define the scope, load policy, and SLAs surrounding the application. Since everything about the software cannot be tested, a decision should be taken to identify the specific area, feature, or functionality of the application for testing. It has been observed that around 10-15% of test scenarios contain around 75-90% of bugs. So, it is better to focus on those scenarios and mitigate the lion’s share of glitches.

How to build the right Application Performance Testing strategy?

Selecting the right strategy would determine if the performance of the application covers all the right areas and load scenarios.

Test environment: Set up a robust test environment by identifying elements like hardware, network configurations, and test tools. This will help the QA team to identify challenges pertaining to performance testing early on in the SDLC. In fact, QA experts can have a number of options in setting up the test environment. These include:

·         A production system containing a smaller number of servers of lower specification

·         A production system comprising a smaller number of servers of similar specification

·         Using the actual production system or its replica

Baseline for user experience: At the beginning of conducting load performance testing, the QA testers should know the level of user satisfaction. So, it is not merely about the number of load times or responsiveness of the application. Identify a baseline for user experience that the application should be tested for.

Performance metrics: Choosing the right performance metrics is important to plan for testing. These include throughput, response time, and constraints. For example, response metrics deal with measuring the performance of an application from a user’s perspective. While volume metrics is about measuring traffic generated by the load testing tool vis-a-vis the application.

Realistic tests: Allowing umpteen number of virtual users to face a server or cluster of servers may not be the right way of measuring load in a real-world scenario. While setting up such a scenario, the focus should be on choosing the devices or environments that would be used to access the application in real-time. This is important because the traffic is likely to come from a host of mobile devices, operating systems, and browsers. Also, the realistic test scenario should vary the test environment. This is to allow the organization to become resilient to the changing market dynamics.

Performance testing a part of Agile: Performance testing should not be conducted at the end of the development process. This makes it too late and expensive to fix glitches. So, load performance testing should be integrated with the development process a la Agile. In fact, performance engineering should be a part of the scrum and entrusted with measuring the performance of code during development.

Conclusion

In a competitive business environment where the quality of software application determines the latter’s success, building the right strategy for performance testing is critical. It ensures the smooth performance of application against a definitive user load scenario.