Load testing is essential for web and mobile applications, because customer satisfaction is tied directly to how well these applications perform. Yet, IT teams sometimes skip load testing because of time or resource constraints, often to the detriment of an application's success.
Application load testing is an extension or subset of performance testing that informs developers if an application is truly ready for prime time. In the current software application environment, the customer is king, and it's essential to keep an application functioning according to user expectations.
There are well-documented and highly publicized examples of application system failures blamed on shoddy performance, which point to lack of load testing. When HealthCare.gov went live, the system failed to handle the load, resulting in the servers crashing; this is one large-scale example of how a lack of application load testing can result in disaster. Incidents like this prove that it is simply bad business management to ignore performance and load-type testing, whether the application is a mobile, web or client/server design.
Companies should add application load testing to their software development plans as an initial step toward performance assurance. They should also plan for dedicated resources to develop, execute and keep load testing up to date so that an application meets customer standards. Customers have many choices in the market and expect an application to execute in a reasonable time frame, regardless of the request. Companies must ensure that the application delivers, even under heavy user loads, traffic spikes, failover switches and situations with network speed variables.
Load testing specs
An effective application load testing suite identifies the normal and maximum operating capacity of an application and can also tell how an application performs during upward and downward spikes of use. Soak load tests provide useful measurements on application performance over time, with variable conditions. In the same manner, spike testing ensures the application can handle extreme and unpredictable loads.
When an application undergoes load testing, testers configure the tool to hit the application with a defined functional test suite to deliver metrics on how the application performs. The system can also provide metrics on how applications perform in up or down spike periods or when a network is in various states.
The purpose of performing all these load test variations is that developers will know exactly where the application needs to improve in order to work effectively under various real-time conditions. Successful application load testing can also find defects before the application is available for mainstream customers. Additionally, load testing tools reveal how effectively a server or cloud failover plan performs. For example, testers can verify how the application handles the time while a server failover executes. The application could pause but should not crash, and users should not be aware of the mechanisms that take place on the back end.
Load testing also identifies problems with error handling in an application.
For mobile and web apps, developers must know if the design can hold up under high demand over low network speed. Mobile app users expect speed and efficiency and won't tolerate slow or poor-performing apps, regardless of their convenience. The same applies for the modern web app user.
Advantages of load testing tools
Developers can independently program load tests, but there are also numerous, quality tools that ease the process without overtasking development resources.
Load testing tools are built to handle the large variety of obstacles an app encounters. Web and mobile applications can fail due to slow network connections, internet connection errors, slow response times and platform compatibility problems. Server failures, slowness or errors can also derail any application. A good application load testing tool provides a range of options to create valid load tests that cover multiple failure points, regardless of coding structure, because the sheer variety of mobile and web devices is massive.
Load testing tools also provide a launch point and test storage location, as well as the ability to automate or schedule test runs. Most tools include training or provide fee-based training, although users don't often need formal training to use the tool. All load testing platforms include online resources and user support sites.
Similar to test management tools, load testing tools can store, develop and execute other performance tests. Application load testing tools provide a single source of application performance data that admins can manipulate and maintain within a single space. Different teams can access the tool, and they can also reuse tests to cover multiple needs.
Build the test foundation
Application load testing, like performance testing, requires a dedicated testing environment complete with valid test data. Load testing on existing testing systems is not realistic and is unlikely to return accurate results because a good QA team manipulates data and sets up error conditions, which creates a large amount of test data that might not be valid. Test data is not stagnant and might not be refreshable back to a pristine state. If load testing adversely impacts the QA system, it can interrupt or delay testing efforts.
Testers should ideally execute load tests on their own system, where the testers create and link valid test data examples to a variety of back-end platforms within the tool. Issue definition is cleaner in a separate system as well.
Effective application load testing segregation ensures that execution metrics are accurate -- the cleaner the data and metrics, the more accurate the load testing results.
When developing load testing scenarios within the tool, keep test environments separate to save maintenance time compared to combined systems. Similar to many automated testing tools, the load testing tool requires pristine data to compare to new result sets. Otherwise, teams spend time to debug tests rather than execute and analyze results.
Useful management metrics
Load testing tools provide a vast array of reportable metrics automatically, such as application and server throughput, error rate and response times to individual functions within the application, as well as CPU utilization, RAM utilization and wait times. In this manner, it's easier to distinguish where and what functional areas need performance fixes. By isolating where errors occur during the test, developers spend less time hunting an error and can more quickly design and code a fix. Most load testing tools also measure and report metrics on how many concurrent users the application can handle before it declines in performance, as well as the number of requests per second the application can handle.
Application load testing tools also provide the ability to detect the number and nature of failed transactions to prevent customer-facing problems. For example, do users abandon an application at a certain point or while it performs a particular function? Load testing metrics can determine if end users experience issues at those identified abandon points.
All members of the software development team from product manager and developer to QA tester benefit from the analysis of load metrics. Product managers might see the need to redesign a function or create a new workflow that better serves the customer and works more efficiently within the application. In this case, more error messages or a better error-handling method might be necessary. For the QA team members, load testing tools provide coverage beyond the typical testing reach and prevent defects that might not be immediately evident in other systems.
With extensive research into the load testing software market, TechTarget editors have focused this series of articles on vendors with considerable market presence and offer load testing tools specifically for application development. Our research included Gartner, Forrester and TechTarget surveys.