Performance testing is a part of software testing which measures the stability and responsiveness of an application under the workload. It also measures other parameters like scalability, reliability, and resource usage. Performance testing is used to make sure that the application meets the benchmark values.
Performance testing is significant because it serves the following purposes:
- It demonstrates the performance of the application so that you can decide if it meets the industry standards.
- It allows you to compare the application scores with another similar application.
- It lets you identify which part of the system or network affects the performance of the application.
- It gives you enough metrics or scores to decide whether it has served its purpose of creation.
8 Types of performance testing
Load testing is a basic form of testing. It is done to know if the application can handle the workload that is expected after launch. The workload could be measured in the number of tasks it can perform at a time or number of users who can use the application at a time. It will also help you to measure the time taken for the application for performing a specific task.
A stress test measures the maximum workload that the application could handle. It tests the robustness of the application in case of an extreme workload.
Soak testing is also called as endurance testing and is done to know if the application can handle the required workload continuously.
Spike test is done to ensure whether the system holds up when there is a sudden increase in the workload. This test will let you know if there is a drop in performance or system will fail or it can handle the spike in workload.
The breakpoint test determines the workload at which the system fails. It is different from the stress test in the objective of the test. Stress test determines the maximum workload the system can handle. The breakpoint test determines the minimum at which the system fails. The workload is increased incrementally to determine the breakpoint.
Instead of varying the workload, the system configurations are changed and tested for performance and behavior. Commonly different methods of load-balancing are employed while testing.
Isolation testing means the repetition of a test in which the system failed to identify the cause of failure. As the name suggests it is done to isolate the fault domain.
The applications are tested on the work environment through physical systems or cloud servers and monitored remotely. This is a new addition to performance testing.
Performance Testing Vs Load Testing
|Performance testing||Load testing|
|Overall test to measure speed, reliability, and scalability||Test to measure response in an expected workload|
|It is both qualitative and quantitative||It just tests with different quantities of load|
|It is the superset of load testing||It is a subset of performance testing|
When performance testing is required?
If you are building an application from scratch, it is difficult to determine whether to test performance from the beginning or at the end.
Testing at the end: Waterfall approach
We wait until the end of development to start testing in the waterfall approach. Testing at the end has both advantages and disadvantages. It is easier to plan performance testing since most of the work is completed except for some finetuning. We can test in an actual work environment and measure scores for specific characteristics. Obtaining the required infrastructure is a hurdle in the waterfall approach. Making architectural changes at the end of development costs more.
Testing from the beginning: Agile approach
In the agile approach, testing is done from the very beginning. A continuous testing environment needs to be engineered in the agile approach. It is risk-free and provides constant feedback. It gives enough time to make any changes that are needed. Some disadvantages include the need to automate testing and develop a strategic plan.
Considering the pros and cons listed above you may choose when to process a performance test.
How to automate performance testing?
To remain competitive in this age of digital transformation, it is important to automate performance testing. The structure of an automated test is different from the usual test. Before automating we need to make sure the following pre-requisites are met:
- Stable applications and systems without significant changes in the immediate future.
- A solid test process already in place.
- A qualified performance test engineer.
- Scope for an initial automation effort.
- Stockholders and the management see test automation as an investment.
Once the automation tool has been selected, the automation approach and the breakdown need to be planned. All technical guidelines must be established and the automation script is written and implemented. To have a positive return on investment proof of concept must be completed perfectly and the automation process needs to be managed properly.
List of Best performance testing tools
There are both opensource and commercial performance testing tools available.
- Apache JMeter
- LoadUI Pro
- Silk Performer
- Rational Performance Tester
Performance testing key skills required
Test engineers need both technical and non-technical skills. Some of them are briefed below.
Scripting is the most needed skill for a performance tester unless you are using an automated performance testing tool. Even if you are using an automated performance testing tool, scripting skills are needed to make any personalization. Depending on the tool use the scripting language will vary.
- Understanding of system architecture is also important for planning and preparing the performance test.
- Designing effective tests includes identifying goals, requirements, and schedules.
- Interpreting performance test results is needed to identify bottlenecks and other issues.
- Understanding customer behavior is a must for any business or application to run successfully.
- Problem-solving skills are needed to rectify and optimize the application if needed.
Performance testing interview questions
Here are some of the frequently asked performance testing Interview questions.
Performance testing is the process of measuring the speed, reliability, scalability and resource usage of an application. It is significant to test the performance before releasing a developed application in the market.
Poor or outdated coding
Unoptimized or unmanaged databases
An unexpected spike in load
Malfunction of third-party services
System or application configurations
DNS, server, and network issues
A performance bottleneck occurs when a part of the system is unable to keep up with the others. Some common bottleneck issues that are:
Rational Performance Tester
Performance Testing process includes the following steps/phases
1 – Determining the right testing environment (hardware, software and network configuration)
2 – Identifying the performance metrics: Goals for throughput, response times and resource allocation
3 – Planning and designing performance tests
4 – Configuring the test environment
5 – Implementation of the designed performance
6 – Monitoring the test process
7 – Analyze the results, make the necessary change and run it again.
These are the parameters considered in performance testing:
CPU interrupts per second
Disk queue length
Network output queue length
Network bytes total per second
Throughput – rate a computer or network receives requests per second.
Amount of connection pooling
Maximum active sessions
Hits per second
These are important factors to consider while selecting a performance testing tool.
Compatibility with the customer work environment
Availability of infrastructure
Funding approved by the management
Efficiency of tool
Availability of Manual and automated Testing
The common mistakes done in performance testing are
Incorrect workload models
Incorrect user think time
Outdated or hardcoded data
Ignoring certain script errors
Overloading: too many concurrent users
CPU and Network configuration
Performance profilers are software development tools designed to identify and rectify poorly performing sections of the code. It is a necessary tool during the development and quality analysis process.