What are Non Functional Testing Types with Examples & Tools

When buying a house, what will you notice first? The structure, the design, its capacity, location security, and many more things. Only later will you notice the plumbing or electricity issues that are buried behind the wall. While both options are equally important, the visual ones appear before the wrapped ones. 

The same happens in software testing. Both functional and non-functional issues are essential. But, users will notice non-functional defects before identifying functional ones. And so, we think understanding non-functional testing types to avoid such noticeable bugs is necessary. It will ensure that customers do not leave from your website or application even before they get to know it.

What is Non-Functional Testing?

Non-functional testing is a testing type that validates the non-functional aspects of an application or software. It tests the overall performance and user experience of the system as per non-functional parameters, which are not available under functional testing. Non-functional testing is equally critical as functional testing and affects customer satisfaction at the same level as well.

It pertains to the reliability, performance, security, usability, and scalability of the product. 

Objectives

The goal of non-functional testing is to check and improve the performance of the system with all its modules and functions intact. Some of the major objectives of non-functional testing are:

• It should evaluate the usability, scalability, compatibility, efficiency, and maintainability of the system.
• The results from non-functional testing should help improve overall performance and customer satisfaction.
• This testing helps to reduce the cost associated with setup, installation, and maintenance of the system.
• It also focuses on checking whether the system adheres to industry standards, regulatory requirements, and legal obligations.
• Non-functional testing also takes into account the system’s response time, throughput, resource usage, and scalability under varying load conditions to ensure it meets performance requirements.

Read all about Non-Functional Testing

Non Functional Testing Types

Non Functional Testing Types span more than the performance and security aspects of the software. There are multiple types of non-functional testing that are all focused on improving the way a system interacts with the users. 

• Performance Testing
• Compatibility Testing
• Load Testing
• Usability Testing
• Failover Testing
• Stress Testing
• Scalability Testing
• Maintainability Testing
• Volume Testing
• Recovery Testing
• Security Testing
• Portability Testing
• Compliance Testing
• Efficiency Testing
• Endurance Testing
• Reliability Testing
• Visual Testing
• Internationalization Testing
• Localization Testing

Many of these options can be combined under one umbrella term. For instance, performance testing can include checking the load and efficiency of the system.

Right now, let’s focus on some of the Non Functional Testing Types in detail below,

1. Performance Testing

Performance Testing checks how well the software works. It helps to identify and eliminate performance-related issues of the product, such as load speed, stability, scalability, and reliability of the system.

But prior to performing the tests, you must define the expected outcome. If not, it might be difficult to determine if the test was a success or failure.

Example:

The product’s loading time should not exceed 5 seconds for at least 5000 or more clicks simultaneously.

Tools Preferred:

• Apache JMeter
• LoadNinja
• Headspin

2. Load Testing

Load testing determines the loading capacity of the website or application. That is, the number of concurrent users a system can handle at one time. You can define this testing as a part of performance testing. It helps test if the product is working as expected under both normal and heavy traffic.

Example:

• Check that the mail server can handle thousands of concurrent users.
• Testing an e-commerce application by simulating thousands of users making purchases simultaneously.

Tools Preferred:

• Neotys Neoload
• JMeter
• Parasoft Load Test

3. Security Testing

Security testing identifies the application’s ability to protect itself against security threats and unauthorized access. It helps identify the security weaknesses in the system.

This testing is done by looking into the system from an attacker’s perspective.

Also, you need to identify the parts of the code that an attacker will most likely attack. By doing so, you can create robust products.

Example: 

Suppose a financial institute is reforming its security guidelines and introducing new privacy protocols to safeguard customer data. Performing penetration testing on a bank application to identify security vulnerabilities in such cases is a way to do so.

Tools Preferred:

• ImmuniWeb
• Vega
• Google Nogotofail

4. Portability Testing

Portability testing helps test if the software can run on different operating systems without any issues. The functionality of the product under the same platform but with different hardware will also be tested.

Example:

Let’s take the example of Testsigma website. It should work on desktops, smartphones, and iPads. Simultaneously, it should also be supported on different OS, such as Windows, Android, and iOS, to name a few. Running portability testing on the website will ensure that it is working properly throughout varying systems and OS.

Tools Preferred:

• Testsigma

Automate your portability tests, for better efficiency and effectiveness, with Testsigma

• BrowserStack
• Sauce Labs

5. Compatibility Testing

This testing helps verify that the software or system is compatible with other software or systems. That is, checking if the product is compatible with different software, hardware, and network configurations.

Further, it helps make sure that the application is cross-browser compatible and provides a seamless and user-friendly experience across various browsers, devices, platforms, and versions.

Example:

Testing if the mobile application is compatible across different operating systems, versions, and devices.

Tools Preferred:

• Testsigma
• BrowserStack
• LambdaTest

6. Usability Testing

Usability testing identifies if the application is easy to use and accessible for users. Statistics state that 97% of users consider ease of use as the highest quality for mobile applications. Clearly, companies need to give attention to usability testing as an important aspect of an application. 

Example:

• Checking if the navigation within the product is clear and easy to use.
• Verify the design is simple and clutter-free.
• Check if the logo redirects to the homepage.

Tools Preferred:

• Maze
• Optimal Workshop
• UsabilityHub

8. Reliability Testing

Reliability testing helps test if the application is working correctly under predetermined parameters without causing errors. The product will be tested for a specific period of time in a specified environment to check its reliability.

Example:

Suppose we are testing Testsigma, the test automation tool. We have large, complex test cases that need to run. Reliability testing would be to check if the test automation tool Testsigma can handle such vast test cases and continue executing the steps as long as you need without breaking in the middle.

Side note: Testsigma can execute long, complex test cases as per your business requirements.

Tools Preferred:

• ReliaSoft
• Apache JMeter
• Vegeta

9. Efficiency Testing

Efficiency testing evaluates the software application’s ability to utilize resources efficiently under various conditions. The main objective of efficiency testing is to measure how well the system optimizes and utilizes its resources, such as CPU, memory, network, and storage while performing specific tasks. 

Example:

Let’s consider that multiple users are accessing a specific webpage concurrently. Efficiency testing ensures the application performs efficiently under load, providing fast and responsive user experiences without resource bottlenecks or performance degradation. The test results help optimize resource utilization and improve overall system efficiency.

Tools Preferred:

• WebLOAD
• JMeter
• LoadNinja

10. Volume Testing

Volume testing is a type of software testing that helps evaluate the performance and behavior of the software when it is exposed to a large volume of data. It is also called flood testing.

This testing helps identify performance issues, such as slow response time, memory leaks, or crashes, that may occur when the system handles high data volumes.

Example:

Test the behavior of a music application when thousands of users listen to songs at once. Or check how an online reader app works when multiple users are accessing it at one time.

Tools Preferred:

• HammerDB
• NoSQLMap
• DbFit

11. Recovery Testing

Recovery testing determines how well a product can recover from a crash, network failure, hardware failure, and other unexpected issues. This helps ensure the application can quickly and efficiently return to its normal state after a failure or disruption.

During recovery testing, testers intentionally introduce faults, such as system crashes, network failures, or power outages, to observe how the system responds and recovers. It is also known as disaster recovery testing.

Example:

• Check if the system gets back to a normal state after the network is unavailable and is available after some time again.
• Check if the system responds to users after a server overload.

Tools Preferred:

• RestAssured
• TestCafe
• Cypress

12. Responsiveness Testing

Responsiveness testing helps ensure that the website or application works properly on different devices, platforms, screen sizes, and resolutions. It is important because people use a wide range of devices to access websites and applications, including smartphones, tablets, laptops, and desktops.

According to reports, 50% of users will not prefer to use a website if it is not mobile-friendly, even if they like the business. That is why it is highly important to test the responsiveness of an application to make sure it adapts to any screen, device, or platform.

Responsiveness testing identifies issues, such as text being too small, button issues, or layout issues. Testers usually automate responsive testing using automation testing platforms as it saves time, cost, and effort.

Example:

• Check if the button height and width are the same on all devices.
• Check if the font style is the same as expected on all devices.

Testsigma has multiple options to choose from to check the responsiveness of the software. You can see in the image below that before running the test, you can choose the device and OS combination.

Tools Preferred:

• Testsigma
• BrowserStack
• Responsinator

13. Stress Testing

Stress testing helps verify the stability of software under extreme conditions. Here, testers measure the application’s error-handling capabilities and robustness under heavy load conditions that are beyond its normal operational capacity. This helps identify the breaking point of a system and how well it can handle unexpected or heavy loads.

Example:

Picture a scenario where Amazon launches a big festive sale, and the application witnesses a heavy spike in traffic as millions of users access it simultaneously.

Testers will have to test if the e-commerce app can handle millions of users simultaneously for the period of the sale.

Tools Preferred:

• LoadRunner
• JMeter
• Neo load

14. Visual Testing

Visual testing helps find even the minimal bugs or defects in the UI. It is sometimes referred to as visual UI testing. It validates if the user interface appears correctly across various devices, platforms, and versions.

Let’s take an example to understand this better. Typically visual testing usually involves comparing the different visual outputs against the expected design.

Testsigma allows you to automate visual testing. The how-to-doit part is pretty simple. Make sure to enable the option Enable visual testing for a step while creating your test cases. Alternatively, you can bulk-select the test cases and enable the option.

Now, Testsigma will capture screenshots of the application or website and compare them against a base image to detect any visual differences or anomalies in the design.

After successful execution, you’ll find a red or green camera icon under every test case. Green represents that there are no visual differences, whereas red represents that there is a visual difference.

On clicking the red camera icon, you can easily find the visual differences as Testsigma highlights them for easy identification.

Example: Verify that the dropdown list appears as expected.

Tools Preferred:

• Testsigma
• Percy
• Kobiton

Conclusion

Non-functional testing is as essential as functional testing. It attracts and retains customers before they even learn the functional aspect of the product. That is because all the non-functional features contribute to the end-user experience. We have discussed examples, tools, and how Testsigma is the perfect non-functional testing tool for visual and compatibility testing.

You can click here for a demo and see it all for yourself.

Frequently Asked Questions

What is an example of a non-functional test case?

An example of a non-functional test case will be to verify if the system is able to support an influx of multiple users simultaneously. The test case will have below steps:

• Identify maximum expected concurrent users.
• Set up a production-like test environment.
• Configure load testing tool for expected user load.
• Execute test scenarios, monitoring performance metrics.
• Check for bottlenecks, errors, or anomalies.
• Measure and record performance indicators.
• Increase user load to test scalability.
• Analyze results against performance criteria.
• Document issues and perform root cause analysis.
• Report findings and provide recommendations.

Is API testing non-functional?

API testing can be both functional and non-functional. Non-functional testing of API includes checking the performance, security, and scalability of the API.

Suggested Reading

Automated Functional Testing

Functional Testing VS Non Functional Testing: Differences