Load Testing Using LoadUI – A Free and Open Source Load Testing Tool

What is LoadUI?

LoadUI is an open-source and free tool for load testing that allows you to easily perform complex load tests and test performance by simply dragging and arranging different components.

LoadUI enables the creation and updating of test cases while the tests are running. Its power lies in its user-friendly visual interface and intuitive design, along with the flexibility to make changes during the test.

How Does LoadUI Function?

LoadUI operates on the basis of building blocks known as Components, which are dragged from the component Toolbar to the Project being worked on. These components can be connected to each other using wires, and there is no limit to the number of components that can be created or connected.

This drag-and-drop testing method is particularly valuable during the test since it enables the execution of complex load tests. The comprehensive overview allows for easy experimentation with different combinations during the actual test and immediate responsiveness to them. In LoadUI, instant feedback is highly regarded.

Creating Load Tests in LoadUI

In order to run a test using loadUI, at least two components are required (along with an empty project);

– A generator: This generates a certain load, such as 100 requests per second.
– A Runner: This executes a specific type of test, such as a web test.

So, let’s do it: drag out a Fixed Rate Generator and a Web Page Runner.

However, they cannot be run yet. First, you need to connect them by linking the nodes or terminals located above and below the components using connections.

Now connect the Fixed Rate Generator to the Web Page Runner.

With everything connected, enter the website you want to load test into the Web Page Runner. Your test is now ready to be run! Click the play button in the top menu to start sending requests to your site.

You can keep track of the test progress in real-time by clicking the Results Workbench button. Once there, double-click on your Current Run and, from the left-hand menu, add the Response Time widget to the rack.

Congratulations! You have successfully created your first load test using LoadUI. Explore the widgets on your dashboard, add more as desired, and track other values in the Results Workbench.

A good next step would be adding an Assertion component and connecting it to the Web Page Runner. This will enable you to test how many times your requests meet specific rules (e.g., taking less than 10 milliseconds).

Pro Tips

Let the Manager Test!

This modern approach involves having someone less proficient conduct the testing to uncover any issues with your service. It also fosters an understanding of and passion for testing within the management team. The usual feedback is, “This is fun! But challenging…”

Take Advantage of Interactivity

LoadUI provides highly interactive and real-time configurable features. Make the most of this by simultaneously creating a second test on the same server using a different Generator. Look for any weaknesses the system may have when exposed to chaotic, lifelike behavior. Experiment and make changes in real-time.

Record Your Tests

Because LoadUI is highly interactive, reproducing tests can be difficult. Consider using a screen recording tool like Wink (which is free) to replay your tests and identify what caused the service to crash.

Follow a Structured Approach

LoadUI supports test cases. Break down your tests into smaller test cases that can be started concurrently.

Avoid Redundant Work

If you have already created functional tests in soapUI, you can simply run them in loadUI using the soapUI component. This eliminates the need to redefine tests in loadUI.

Create Your Own Components

In addition to being free, LoadUI is open-source. This means you can write your own components using Groovy if desired. LoadUI has no limits other than those you set! Learn more about creating your own components here.

For additional information on LoadUI and to download the tool, visit Latest LoadUI version

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About the Author:

This guest article was written by Henrik Olsson, a software developer for loadUI based in Stockholm, Sweden. Henrik has an academic background in Distributed Systems and a passion for usability. He has experience in teaching and believes that most things can be easily explained with accurate targeting and effective modeling.

Editor’s Note: I am delighted to share this open-source load testing tool with my readers. LoadUI and soapUI are the best open-source software testing tools from the trusted company Eviware (now SmartBear). If you are considering adopting a load testing tool for your project, give LoadUI and soapUI (functional testing tool) a try.

I have personally used SoapUI for many projects and will soon cover it in a separate article. I am impressed by the power and elegance of these open-source tools!

If you are already using this tool and have some tips to share, please leave them in the comment section below. We are also happy to hear and address any queries you may have about LoadUI.