Load Testing

Load Testing is a performance testing in which the software is made to face minimum and maximum load which is possible from the real-world users and analyzing the performance under the applied load.

Load Testing is a non-functional software testing and is very important for knowing the absolute performance of the software under the load. This testing can assure that the software will not break till the tested load threshold, and thus gives confidence to the developer on their product.

load-testing-demo

While carrying out a load test, there are many approaches one may follow. It can be manual with real-world users or automated using simulators. In case of software where there are similar kinds of tasks carried out, a simulator can be used, to create test scenario or test cases automatically and apply into the software.

While in case of the software which requires fresh data or real-time data, or different settings that needs to be set while using the software. In such cases, there may be a need for manual testing.

Below diagram will make the idea clear:

load-testing-scope

As we have seen in the above diagram, there are different attributes or parameters which are related to load testing.

Basis Path Testing

Goals of Load Testing

Analyze the load bearing capacity:

As the name suggests, load testing allows us to analyze the load-bearing capacity of the software. The developer must be aware of the capacity of the software because, in an emergency, they would require a threshold for the load.

Study of Response Time :

It is seen in the case of different softwares, that the response time differs and tends to increase with the increase in load on the software. Therefore, though response time is purely a performance testing, also is a remarkable attribute in load testing also.

Study the performance of the Database:

Not only for the web application or the software but also load testing is required to check how the server performs when connected to the software.

It is seen in many cases that, the software itself is not responsible for the increase in the response time, but it happens due to the increase of access time of the server, but this time is added to the response time of the software itself.

Calculation of network delay:

This is the time, it takes for the packet to travel through the network and reach the server and travel back to the client. This may seem that the delay is being created on the server side, but that's not true.

This delay is created by the network itself and due to several problems, such as the speed of the connection, the network arrangements, the efficiencies of the hubs, switches, routers, etc.

The detail which is created after the load testing contains attributes such as uptime, number of requests failed, response time, which gives a semi-clear idea about the origin of the network element which is creating the delay.

Analyzing the Configuration of servers:

A load test can also be helpful to understand, how the servers are configured. An abnormal shutdown in the software will indicate that servers are getting disconnected or are not well configured.

Generally, the load test is performed only on the software, that is on the client side only. But since the software is connected to the server, therefore, it directly shows the delay and the responses the server is generating during the load.

Finding faults:

Load testing is one of the easiest ways to figure out faults in the software. Generally, load testing is not used as a bug detector, but it's helpful in time. There are several modules and functionalities which are known to the developers, and the time taken by the modules in the unusual environment are also known.

Now when a delay happens during a load, all the modules need not be checked and directly the bugs generating modules can be checked. This will decrease the time for cross-checking the software itself for bugs. Therefore, load test can also be a part of the unit testing as well, if considered that way.

Compliance Testing

Pre-Requisites for Load Testing:

If the Load Testing is not carried out in a good environment with required set-up, then the actual performance of the software will never be known and fake results will appear which may confuse the tester and bring a different image of the software itself.

Software:

The required software, add-ons and plug-ins are to be installed and the complete environment must be set-up before the test begins. If proper software requirements are not maintained then a normal test cannot be expected.

For example: If an internet browser is using an outdated plugin, then simply testing the load-bearing capacity of the browser will not produce real results.

Hardware:

A software is installed on the hardware, and thus the performance of the software is fully dependent on the software. It does not matter how much efficient the software is, but if the hardware used is not as what is recommended for the software, then real load testing cannot be carried out.

For example, A browser requires a minimal CPU clock speed of 2.3 GHz and 4 GB of Primary memory to perform as normal.

Now if the clock speed is 1.9 GHz and the primary memory connected is 2 GB, then before reaching the threshold of load-bearing capacity, the software or the web-application will start to refect improper results. And that load test report cannot be relied on.

Network Connectivity:

Nothing can work without good network connectivity. The software may be very efficient, and load bearing capacity may be commendable. And also the hardware may be properly configured as per the requirement, but if the network connection is slow, then the software cannot perform.

Almost all the software ranging from a simple text editor to a commercial website is connected through/to the internet. Therefore, the request made to the software has to travel through the network and reach the machine to perform the task. This network connectivity has a great impact on load balancing.

Sanity Testing

Steps for performing Load Testing

Creating the environment:

Before Load Testing begins, the recommended environment must be set-up. Setting-up environment means configuring the required hardware, software, connection or any other pre-requisites.

If the load test is not performed in the right environment, the actual data will never be reflected.

For example, to set up a load testing for a web application, we require, an updated Operating System, an updated inter-browser and good internet speed all installed in hardware with fine processing speed and addressable memory.

Creating the Test Scenario:

Test Scenario means the situations or the data acquired/ collected/gathered manually or automatically by the software for by users. Now this test scenario will be used by the Load Testing software to create the load test report.

For example, we can see in the case of Gatling which is a load testing tool for a web application, the scenarios are created in a scale file and then the software converts the file into a report.

Creating the Test Report:

The report can be created by running the simulations on the load testing tool. For example, as we have seen in our Gatling tutorial, the simulations are stored in the folder simulations of the Gatling directory, as a scala file. The scale file is then fed into the software to get the report.

Making the report available to the experts:

The report is then made available to the experts who then will analyze them report to arrive in a conclusion, whether the performance.

Scalability Testing

Examples of Load Generation Scenarios

Promotion Period:

Generally, it is seen in the promotion period, when there are attractive offers in commercial websites, airlines, cinemas, etc, then the request made into the web application is much higher compared to the normal days. In such cases, the website suffers a load.

Due Dates:

Mainly, in government websites when the due date approaches or when it is the due date itself for filling up certain forms of examinations or registrations, then the request made into the web application is abnormally higher compared to the normal days, and the website suffers a load.

Fake Request:

There can be a hacker who can create fake request and with the help of a simulator may try to send concurrent requests to the server. Despite the fact that those are empty requests, but are counted a normal request and is like a heavy load on the server.

Direct Memory Access:

This is a protocol where the access of the file is directly made from the disk or the storage and the CPU cycle is stolen, which can create a heavy load on the system. The DMA is the only transfer in the system which is carried out in a speed which is almost the access speed of the storage or the drive.

Downloading:

There are several websites, where there are download links of different kinds of software which are huge in size. When the size of the software is much larger, the website may not be able to bypass such software and may hang.

Spooling:

This is a technique through which the data used by the system such as printers, machines, etc are copied into the Cache memory of the devices so that the process can continue with efficient speed without being interrupted.

Even the disconnection of the computer or the software will not interrupt the current process. But the problem is that the cache memory inside the devices is very small in size, limited to some MegaBytes only. Also, there is a provision of queuing the data, and that creates a problem of overloading of data in the cache.

Also, a device may be eligible to perform various kinds of tasks, but only one at a time. Now when different kinds of tasks are queued in the cache, then it is an overload.

Types of testing in brief

Advantages of Load Testing

Making the system stable:

The system can be only made stable when the load-bearing capacity of the software will be known by the developer.

The word stability signifies that when the load crosses the threshold for the software, then also, the parameters such as response time, access time, load time, etc should not deviate much from the normal value.

Improving the scalability:

It is very important to know about the breakpoint of the software and analyzing the bottleneck of the particular software. Because to apply the software into different areas it is necessary to have an idea of how it would behave with a different load on it.

To make a software scalable, the actual performance of the software under normal and load conditions should be known. Because when different people with less technical knowledge uses the software, they would like to apply the maximum load possible in their business.

Customer Satisfaction:

A software not able to work in load condition will be never acceptable to the customers. If there is a threshold of load in software, then also the accurate breakpoint for the software should be made available to the customers as a manual or warning, so that they know when

Test case in Software Testing

Load Testing Tools

  • Gatling: This is a load and performance testing tool mainly used to test the performance of the web application of the web page. It is a scala based software, which primarily creates the report in scala.
  • Apache JMeter: This is an open source load testing tool mainly designed to analyze the functional behavior and load of many web applications as well as other softwares also. It is based on Java.
  • LoadNinja: It is a cloud-based load testing tool. This mainly targets the load-bearing capacity of the servers and check for the scalability of the software along with the robustness.
  • LoadRunner: LoadRunner is also a popular load testing tool used for different applications. It can simulate thousands of real world users in a concurrent manner to create a real load in the software.
  • LoadView: This is an On-Demand load testing software used for making numerous realistic requests on the software and checks the load.

There are several other load and performance testing tool available.

Software Testing Techniques

Summary

Load Testing is one of the software testing technique(belongs to performance testing) in which, the performance, efficiency, and usability of the software are tested when the software is under load.

A load on software means when more number of requests or queries are made to the software than the usual capacity of the software. Load Testing is helpful in determining the response time, efficiency, and overall performance of the software under load.

There are different goals of carrying out load testing. They are, making the software scalable, efficient, bugs removal, good response time, etc.

To carry out an unbiased load testing the hardware and the software requirements are to be fulfilled. The CPU speed, the primary memory, the cache are a major concern while carrying out load testing. Moreover, server, the network, the internet speed are all to be taken care of while testing.

There can be different factors which are responsible for creating load in the software. They are huge traffic on the website due to a reduction in the sale of items, tickets, booking, etc. Mainly the government websites suffer load at the due time of filling up different forms and carrying out different registrations.

Not only on the website, but load testing is applicable to any kind of software. There are different load testing tools available on the internet as open source and some are paid. Some examples are LoadNinja, StressStimulus, LoadUI Pro, LoadView, NeoLoad, WebLoad, AutoMail, JMeter, LoadRunner, Gatling, etc.

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