Application developers need to ensure that their applications are tested and perfect in all respects before being sent for production and market. Not doing appropriate tests can lead to the danger of faulty applications, which when released without adequate testing, can seriously damage the reputation of the business. One of the critical testing that needs to be carried out, for an application, is performance testing.
Performance testing of an application entails testing the speed of the application to verify whether it meets the expected criteria of the customers. It can be used to detect bottlenecks in the application that can slow down the entire system. This can be a mix of pre-described test cases in a test suite run on a test-setup or executing ad-hoc test cases, depending upon the expertise of the testers. Performance testing includes stability, reliability tests and shares some common ground with load and stress testing as well. If you want to ensure that your application is reliable, it should do what it is supposed to do. Taking the help of an expert quality assurance software testing outsourcing service provider can be the right move to help you build and market a sturdy application.
The Need to Define Objectives
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It is important to define clear-cut objectives of performance testing, so that the testing itself can be made more efficient. Such pre-defined and well agreed objectives can lead to better evaluation of the performance of the application vis-a-vis the objectives. It is often useful to define both qualitative and quantitative objectives for performance testing.
3 Key Application Performance Testing Objectives
The main objectives of performance testing should include the following:
Defining The Metrics And Measurements For AUT (Application Under Test):
It is vital to understand what defines a ‘good’ performance level. Metrics need to be clearly defined that will indicate the performance of the application. Most commonly used metrics are:
- Application Response Time: The amount of time the application takes to respond to a request. This can be separately measured at the client as well as the server for different values.
- System Resource Utilization: Resources such as CPU, I/O, memory and database are used by a typical application. Hence there are parameters that can measure the utilization of each of these. This can be defined atomically per transaction or per operation.
- Application Throughput: This can be measured as the number of transactions done by the AUT in a given time period, say per second, and it depends upon the load.
- Workload : This measures how many concurrent tasks or users the application can handle at a given time.
Once the metrics are decided, it is important to run the test cases multiple times on various setups and during all the deployments to get a practical range of acceptable values for each metric. This can work as a baseline for future measurements. The minimum acceptable thresholds of each parameter can also be defined. Recollecting information from the application running over a long period and thus re-baselining the values of these metrics is very important. This must be done periodically and surely after every upgrade or added functionality to an existing application. A software application development expert would ensure that all these metrics are in place for gauging the performance testing.
Making Effective Test Cases:
As with any other testing, a performance testing activity is as effective as its test cases. Careful planning, thoughtfully discussed with system and resource experts as well as application designers, is necessary to plan the performance test suite. Test cases need to be a mix of tests that check the:
- Reliability of the AUT.
- Stability under heavy load.
- Capacity – What is the point of degradation of the application?
- Regression – The effect of new functionality on existing performance, such as response time.
- Varying user load – The behavior of the application under user ramp-up, user peak load, and ramp down loads.
Meaningful Analysis Of The Test Results:
It is important to perform the test cases and mark them passed as per defined criteria. But it is even more essential that the performance test results be reviewed for a thorough analysis by experts, over and above the analysis by the actual testers. The results can then be used to define goals for improvement of the application’s performance. In case the performance levels are not within the acceptable levels as per the specified criteria, system level expertise is mostly needed to be able to identify the bottlenecks causing performance degradation. The right analysis can also help identify whether the product is ready for shipment/deployment, what is the maximum capacity and which configuration helps it run most effectively. Performance of an application gives an indication of its efficiency and time responsiveness. It gives the confidence that the software would not buckle up under too many simultaneous users and that the users/customers will not face long wait times or delays. If the performance requirements of the application are defined well in clear, concise, verifiable terms, it can help make useful test cases.
The main aim of performance testing is not to find errors, but rather to test the application for weaknesses and bottlenecks, to remove these, and build a robust product. It also acts as a baseline for further regression testing. Enterprises that do not give due weightage to performance testing may find their products throwing up surprises with unhappy customers and users when the application is exposed to actual load.