In this section, we are going to understand load testing, which is the important part of Performance testing and used to check the performance of the software by applying some load.
And we also learn about its process, why we need to perform the load testing, the objective of load testing, example, various strategies of load Testing, advantage and disadvantage.
Introduction of Load Testing
In software testing, load testing is an integral part of performance testing under non-functional testing.
Load testing is testing where we check an application's performance by applying some load, which is either less than or equal to the desired load.
Here, load means that when N-number of users using the application simultaneously or sending the request to the server at a time.
Load testing will help to detect the maximum operating capacity of an application and any blockages or bottlenecks.
It governs how the software application performs while being accessed by several users at the same time.
The load testing is mainly used to test the Client/Server's performance and applications that are web-based.
In other words, we can say the load testing is used to find whether the organization used for compering the application is necessary or not, and the performance of the application is maintained when it is at the maximum of its user load.
Generally, load testing is used to signify how many concurrent users handle the application and the application's scale in terms of hardware, network capacity etc.
The Objective of Load Testing
The main objective of using the load testing is to fulfill the following aspects:
- The load testing is used to perform the maximum quantity of software applications without important performance breakdown.
- It is used to govern the scalability of the application and allows various users to access it.
- It is used to identify the total count of users that can access the application simultaneously.
- The load testing is used to determine whether the latest infrastructure can run the software application or not and determine the sustainability of the application concerning extreme user load.
Why is load testing important?
The load testing is essential because of the following factor:
- It guarantees the system and its consistency and performance.
- The load testing is necessary if any code changes occur in the application that may affect the application's performance.
- It is important because it reproduces the real user scenarios.
- It helps find the system's bottlenecks.
Rules for load testing
During the execution of the load testing, a test engineer should follow the below rules:
- A test engineer tries to evade downloading images on the site.
- Once the application becomes functionally stable, load testing should be planned.
- The reliability of response time concludes the past period should be logged and the same should be compared with several test runs.
- For each scenario or script number of users should be decided.
Load Testing Process
The Load testing process will be completed in the following steps:
Step1: Test environment setup
- In the first step, we will set up the test environment to execute the load testing to ensure the testing can be done appropriately.
- And the test environment should be set up near to the production environment as likely in terms of network, hardware, software specifications etc.
Step2: Load the test scenario or specify the performance criteria
- In the next step, we will define the performance criteria, which contain the response time, reasonable limits on throughput, and the load test transaction.
- And then, we create the load test scenarios, which ensure the success criteria are finalized.
- In the load testing, transactions are decided for an application
and data is set for each transaction.
Note: A test scenario is a combination of scripts, and virtual users executed during a testing session. The Scenarios could be of two types, either manual or goal oriented.
For example, In the LoadRunner testing tool, the scenarios are created with the LoadRunner controller's help.
Step3: Execution of test scenarios
- Once we successfully create the load test scenarios, we will execute the particular test scenarios.
- But before we execute the load test scenarios, we have to set the different configurations and matrices to collect the information.
- The load on the server is matched by consecutively several virtual users to complete the tasks concurrently.
- And we can execute the entire scenario in virtual user groups or individual virtual users.
Step4: Analysis of the test result
- After executing the load test scenarios, we will analyze the test results.
- The load test Scenario can be inspected with the help of LoadRunner online monitors like:
- System resource
- Run-time transaction
- Network delay
- Web resource
- The last step of the load testing process depends on the test result because if the test fails, we have to perform the same process repeatedly until the test result is passed and all the issues and bottlenecks are fixed.
Examples of Load Testing
Let see some real-time example where we can see the massive failure of the particular application as they did not perform the load testing:
E-commerce websites capitalize deeply in advertising campaigns but not in Load Testing to guarantee ideal system performance, and they get massive users at the same time. Because of that, some very popular sites have suffered a serious failure
Amazon lost $66,000-$66,240 per minute because the amazon.com server crashed heavily by users' traffic for 30 minutes in 2013.
And during a festival offer, an Airline website cannot handle 10000+ users at the same time.
More people have a habit of booking a flight ticket throughout holidays or on the days when an air company has an offer.
As we can see, more people incline to buy products during a promotional event like Diwali, Black Friday, big billion days sales.
And if a website or an application crashes in such an event, users may leave the website and go to a competitor's application, leading to loss of revenue and market share. Those scenarios may occur because we do not perform the load testing on the system.
Note: Based on a survey if a site is crashed or slow, 70-75% of the users would leave the website. If the website or an application did not load in 3 seconds, 40-50% of the users said they would buy elsewhere.
Difference between Load and Stress testing
The major difference between load and stress testing is listed in the following table:
|Using load testing, the test engineer can detect the bottleneck and tell the cause of bottlenecks before deployment to the production server.
|By using Stress testing, the test engineer can check the system capacity when the number of users suddenly increases before the system failure or crashes.
Refers to the below link to see the more difference between load and stress testing:
Types of Load Testing tools
We have the various type of load testing tools to execute the load testing, which is as follows:
Load Testing Tools [Open-Source]
- To perform the load testing, we can use the open-source load testing tools as we have various load testing tools available in the market for free of cost.
- If we have a limited budget for the particular project, we can use open-source tools. But not every time, as they may not be as advanced as the paid load testing tool.
- JMeter is the most frequently used open-source load testing tool.
Manual Load Testing
- One of the most effective load testing approaches is the manual process to perform the load testing. Still, we cannot rely on it as it does not produce repeatable outputs and assessable stress levels on an application.
- And if we perform the load testing manually, it requires a lot of workforces, which is quite expensive compared to paid tools.
Load Testing Tools [Enterprise-class]
- The paid load testing tools are used to support many protocols; therefore, it can implement various types of applications like Streaming Media, ERP/CRM, etc.
- LoadRunner is the most popular licensed load testing tool.
In house Developed Load Testing Tools
- The particular organization uses the in-house developed load testing tools approaches to build their tools to perform the load tests on their application for understanding the importance of load testing
Load testing tools
We have various types of load testing tools available in the market, where some are commercial tools and open-source tools. Let see some of the most common load testing are as follows:
- Apache JMeter
- HP Performance Tester
To get detailed information about the above load testing tool, refer to the below link:
Advantages and disadvantages of load testing
Some of the vital benefits of performing the load testing are as follows:
- Load testing helps us to detect the bottlenecks and performance-related issues before production.
- The load testing enhances the scalability regarding network, software and database for the system or software application.
- The major advantage of performing the load testing is reducing the cost failures, which also helps us minimize the system interruption risks.
- Customer's satisfaction is enhanced while using the load testing.
Following are the drawbacks of load testing:
- Load testing can only be executed if we have enough knowledge of any programming language as well as testing tools.
- Usage of load testing tools can be an expensive process because pricing depends on the number of virtual users supported.
In the load testing tutorial, we have understood the following aspects of load testing:
- While executing an application's performance testing, the load plays a vital role and helps to learn the software's effectiveness and ability or an application.
- If we ignored the load testing, it might cause financial losses.
- It is specifying as a type of software testingwhich controls a system's performance under real-life load conditions.
- It expands the scalability, performance issues, and constancy of the application before production is available.
- Using the various load testing tools, we can ensure to deliver a quality product that cannot crash while maximum numbers of users using it simultaneously.