What Is Load Testing In Software Testing? Basics, Tools & Practices

Load Testing is a type of Performance Testing that evaluates the behavior of a software application under real-life load scenarios or conditions. In other words, load testing is checking the performance of a system when it is being used by multiple users. Load testing in software testing helps developers understand what exactly is the response time of the system under various load conditions. There is a range of load testing performed on software to validate it to be end-users ready. These tests range from normal load conditions to extreme load conditions.

Definition Of Load Testing

Load Testing can be defined as the practice of building real-life scenarios for a software application to test its scope, scalability, performance, behavior, etc. It is done by simulating multiple user accessibility, simultaneously, at the same time. It is done by putting demand on a system and evaluating its response.

Why Is Load Testing Important?

Load testing in software testing is a very important part of the software development life cycle. It is because it provides the software developers a lot of important insights into discovering system lag, slow page load times, or system crashes. Different levels of traffic are generated on the software to review and validate the software functionality.

Some Key Concepts of Load Testing:

The key concepts of load testing include analyzing the project requirement, building a load-testing strategy, and creating test scenarios and test cases. It usually involves simulating multiple virtual users to send requests at the same time. And then testing and evaluating the performance of the software under extreme load conditions.

Objectives of Load Testing

The objectives of load testing include:

• To improve the software’s overall performance
• To understand and determine if adding new features to the software will make it more capable of solving problems or not
• To understand software behavior under extreme load conditions
• To find out the number of users or transactions that the software can handle
• To understand how far the software can be scalable
• To find room for more improvements in the software

Load Testing Techniques

The most common types of load testing include Stress Testing, Spike Testing, and SOAK testing. Let us learn about them in more detail.

• Stress Testing: Stress testing is done on software to determine the system’s behavior, functionality, and capability to handle load conditions above normal levels of usage.

• Spike Testing: In the spike testing load testing process the QA testers increase or decrease the traffic to check how the software responds to sudden changes.
• Soak Testing: In Soak testing the software is tested to see how it behaves under constant extreme load conditions.

Load Testing Tools

Load Testing Tools play a crucial role in assessing the resilience of software. Some notable Open-source load testing tools in this category include:

• LoadRunner: LoadRunner is a software testing tool from OpenText. It is created to test applications by measuring how systems behave and perform under different loads.
• Gatling: Gatling is an open-source load-testing tool written in Scala, Akka, and Netty. It is known for its high performance and scalability. It allows users to simulate and analyze the behavior of applications, APIs, and microservices.
• Grinder: Grinder is a Java-based open-source load testing framework. It offers flexibility and extensibility for performance testing. Users can script and execute tests using the tool.
• Apache JMeter: Apache JMeter is an open-source, Java-based performance testing tool. It is developed by the Apache Software Foundation. It is widely used for testing the performance and scalability of web applications, databases, and other services.

These tools empower QA testers to evaluate the performance and scalability of applications effectively.

Load Testing Metrics

To evaluate the performance of software, knowing the correct metrics of load testing is very important. These metrics are usually set under various load conditions. It helps the developers have a clearer vision of the software behavior under different test cases. It is usually done by preparing test load test cases also known as scripts. Let’s have a look at these metrics in more detail:

These tools empower QA testers to evaluate the performance and scalability of applications effectively.

Load Testing Metrics

To evaluate the performance of software, knowing the correct metrics of load testing is very important. These metrics are usually set under various load conditions. It helps the developers have a clearer vision of the software behavior under different test cases. It is usually done by preparing test load test cases also known as scripts. Let’s have a look at these metrics in more detail:

• Response Time: One of the main metrics of load testing is response time. Average response time helps determine the amount of time taken by the software to respond to a request placed by the user. It is also helpful in understanding the speed of the software application. Depending on this metric software developers can decide whether to make further implementations of the product or not.
• Rate of Error: The rate of error refers to the percentage of times the software made an error for the total number of requests made by the end user. The rate of error denotes the number of times any software fails to perform its expected response. It helps engineers understand the insufficiencies of the software and areas that need improvement.
• Range of Bandwidth (Throughput): With the help of this metric two things can be determined. First, the bandwidth consumed in responding to the load test script request. Secondly, the amount of data that is used up during the checking of the requests. The unit of this metric is kilobytes.
• Request per Second: The request per second is again measured by the ratio of requests generated on the software application server in one second. It can be any kind of request like clicking on a document or an image file, etc.
• Number of Concurrent Users: With the help of this metric, one can determine the number of users active on the application, at a given time. This metric helps keep count of the number of users the product can handle, without fail, at a particular time.
• Peak time of response: Peak time of response or peak response time refers to the time that the software takes to handle a request. It is used to find out the longest time taken by the software for a particular request.

Load Testing Process

There are five main steps to carry out the Load Testing Process. These steps are as follows:

1. Requirement analysis: This is the first step to any load testing best practices. In this step, the requirement of the project is analyzed and the test environment is set up.
2. Load test scenario: In this step, according to the analysis report, test scenarios are determined for every individual transaction.
3. Test scenario execution: In this step, the environment and scenario set up in the earlier steps are executed.
4. Result Analysis: Now, after every test execution, data is collected and the same data is analyzed in this step.
5. Re-testing: In this step, if any of the tests fail they are performed again to make sure that the issue has been resolved in the software.

How To Perform Load Testing

Load testing best practices include recording the test script with relevant data. The data must include test-related data as well as user data. It is done to ensure that the tests run without any errors. Once the test scenario, test cases, scripts, etc. are defined, run the tests and collect the data. Finally, with the collected data perform data analysis and provide your input, observations, and necessary information for the team of developers to work on.

Load Testing Best Practices

It is not always enough to perform the above-mentioned steps to get the required results. There can still be chances to improve software but as a QA tester, it might skip your eyes. For that reason follow these five load-testing best practices to make sure the software is bulletproof!

• Target the required workload: It is not necessary to always perform load testing on the whole software to find its bottlenecks. Instead, go through the requirement analysis thoroughly and identify the right workload for the desired areas. Create separate test cases for these tests. Be very realistic with your test script production.
• Be well-equipped with updated machines: Make sure the computers you use to perform the load tests are always updated and ready to sustain the virtual workload. Since these machines are instructed to act as real users and generate several requests at the same time, the chances of these computers crashing mid-way always remain during a test. As an efficient QA tester, make sure you are ahead of the game by avoiding the possibility of such issues during a test.
• Develop crisp scripts: It is very easy to create a test script to start your load testing process. But it is not enough! As a QA tester, you must also know that the test script may sometimes overload the machine. Make sure to write test scripts that are light and crisp to avoid such issues.
• Think time optimization: This is an essential part of creating a test script. Think time determines the user behavior during a load testing process. Optimizing the think time will give you enough edge to understand the performance of the software while it interacts with real-time users.
• Data Analysis: The last and most important part of load testing is software testing. In this step, one must scrutinize all the data collected during the testing process.

Advantages and Disadvantages of Load Testing

Load testing has its own set of advantages and disadvantages too. As mentioned earlier, sometimes the load testing script can become heavy on the devices leading to a failure and a crash. Apart from the advantages there are disadvantages too in load testing that one must be aware of. They are:

Advantages of Load Testing

• Enhances the performance of the software
• Improves the scalability of the software application
• Minimizes the risk factor in software
• Reduces the error rate in the software
• Enhances end-user experiences
• Helps detect crucial bottlenecks
• Helps make the software more robust

Disadvantages of Load Testing

• QA testers must know programming otherwise they cannot perform load testing
• Many times these tests need pretty costly tools
• Requires a lot of resources to perform load testing
• The methodology can be very complex
• It is difficult to simulate real-life user behavior

Load Testing vs Stress Testing

The key difference between load testing and stress testing is that load testing is done to understand the normal scope, behavior, and response of the software under various load conditions. Whereas, stress testing is done to understand the software’s capabilities under extreme load conditions. Stress testing is done to understand the breaking point of the software.

Performance Testing vs Load Testing

A lot of people are even confused between performance testing and load testing. The difference between performance and load testing is: that in performance testing various aspects of the software are tested under varying conditions. It is conducted under or above threshold levels to determine the software behavior. Load testing on the other hand is done specifically to understand the number of users that the software can handle at a time. It is done within the threshold levels.

Final Thoughts

Load testing techniques include the simulation of real-world load conditions to test how the software application behaves. The aim of performing Load Testing is to detect bottlenecks in a software application. It also provides valuable insights into the maximum number of users or transactions that a software application can handle at a given time. The load testing process is carried out before the system is deployed. It is done to make sure that the software application can operate according to the expected level of use.