What Is Non-Functional Testing?

Non-functional testing verifies the way software works and how well it works. There are several non-functional testing types, including performance testing, load testing, stress tests, volume tests, security tests, upgrade and installation testing, and recovery tests. All of these fall in the category of non-functional testing types. 

Nonfunctional testing is important. But what's the difference between functional and non-functional testing? Find out more about these differences in this blog, plus get a breakdown of popular non-functional testing types.

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Table of Contents:

• What Is Non-Functional Testing?
• Difference Between Functional and Non-Functional Testing
• Why You Need Non-Functional Testing
• What Are Non-Functional Testing Types?
• Shifting Non-Functional Testing Left

What Is Non-Functional Testing?

Non-functional testing verifies how applications work by examining things like performance, accessibility, and UX. While these properties do not impact the application functionality, they contribute to the overall user experience. 

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Difference Between Functional and Non-Functional Testing Types

The difference between functional testing and non-functional testing is what they test.

Functional testing ensures that the functions and features of the application work properly. Non-functional testing examines other aspects of how well the application works.

Functional testing tests the functionality of an app. Non-functional testing tests the performance of these functions.

Some examples of functional testing include unit testing, integration testing, API testing, exploratory testing, and critical business flow testing, These all test functional aspects of the website or mobile app.

Examples of non-functional testing types are listed down below.

Why You Need Non-Functional Testing

Non-functional testing is just as critical as functional testing. And because teams need to conduct a mix of different types of testing, you need to be doing both.

Non-functional testing makes applications more usable and reliable. Unfortunately, it can often be rushed in an effort to meet release deadlines.

When non-functional testing is overlooked, performance and UX defects can leave users with a bad experience and cause brand damage. Worse, applications could crash with an influx of users. Accessibility defects can result in compliance fines. And their security could be at risk.

The risks associated with leaving non-functional testing to the last minute are why organizations are looking for ways to incorporate non-functional testing types into the sprints themselves. 

What Are Non-Functional Testing Types?

Non-functional testing is an umbrella term. There are many non-functional testing types. Here are some of the most popular examples:

• Accessibility testing — Tests how usable the app is to users with disabilities, such as vision impairment.
• Availability testing — Tests how often the app is accessible and readily available for use.
• Compliance testing — Tests whether an app meets specified requirements or regulations.
• Configuration testing — Tests an app against software and hardware variations.
• Disaster recovery testing — Tests recovery of business-critical applications in emergency situations.
• Endurance testing — Tests an app under a heavy load over an extended period of time.
• Failover testing — Tests an app’s backup system in the event of a system failure. 
• Geolocation testing — Tests location-based scenarios on an app.
• Internationalization testing — Tests if an app can adapt to regional languages and other factors based on location.
• Load testing — Tests an app’s performance under peak conditions.
• Maintainability testing — Tests the app’s ability to update.
• Performance testing — Tests the speed and responsiveness of an app under various conditions.
• Portability testing — Tests how an app transfers from one software or operational environment to another.
• Resilience testing — Tests an app’s ability to perform under stressed conditions.
• Security testing — Tests an app’s security mechanisms to reveal vulnerabilities.
• Scalability testing — Tests an app’s ability to scale up or down as user requests vary.
• Stress testing — Tests an app’s stability under heavy loads or extreme conditions.
• Usability testing — Tests an app’s ease of use.

Shifting Non-Functional Testing Left

The traditional approach towards non-functional testing means it occurs at the end of the software delivery process, sometimes even extending beyond. Too often, non-functional testing is either left to the end of the cycle or done only partially. Or, it’s outsourced externally, where it is performed manually due to a lack of time and automation abilities. 

In these cases, critical tests don’t run in time to fully guarantee the delivery readiness of upcoming releases. This risks brand damage, compliance issues, and worse.

What can be done to fix this?

Modern testing frameworks and cloud-based solutions allow earlier testing in the SDLC. These allow for the identification and resolution of non-functional testing defects. Without non-functional testing early in the cycle, these defects have the potential to delay releases. Therefore, non-functional testing reduces costs, unnecessary effort, and risk.

Early testing also smooths the transition from development to functional and non-functional testing.

Technology is only one half of the equation though. A cultural commitment to Agile principles is also needed. Teams need to constantly monitor and fine-tune their tests so that they are aligned, well-perceived, and trusted.

Bottom Line

Non-functional testing is a critical part of any testing strategy. But it has to be able to scale to your testing needs. 

Our complete continuous testing platform focuses on shifting both your functional and non-functional testing left, offering industry-first support for top testing use cases, such as:

• Mobile UX testing. Understand how your mobile app will perform in real-world conditions while your backend handles millions of users around the globe. Test both your mobile user experience and your backend under load in the cloud and scale up to two million virtual users.  
• Accessibility Testing. Align your accessibility tests with your test cycle and sync your results all in one place with Perfecto’s test reporting. You’ll ensure that accessibility defects are caught earlier when they’re less expensive to fix.

Plus, execute your tests with real user conditions against the thousands of devices and browsers that we support in our cloud-based device lab. 

Experience Non-Functional Testing in Action

See how Perfecto can help you ratchet up your non-functional testing and boost your testing strategy. Get your free trial today.

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