# Development

What is Non-Functional Testing in Software Testing? Types, tools and real examples

Red Rocket TeamDec 11, 20244 min read

Non-Functional Testing in Software QA – What is It? Importance of Non-Functional Testing in Ensuring Software Quality Difference Between Functional and Non-Functional Testing Types of Non-Functional Testing in Software Testing Tools and Methodologies for Optimal Results Example of Non-Functional Testing in High-Traffic Applications

Experts predict the global software development market will be valued at $620 billion in 8 years. This demonstrates the development of technology at a rapid pace and the trend towards the use of digital products all over the world. However, the approach of developers to create these programs will change almost nothing.

One of the most important steps in the entire process is testing. Professional program testers look for the most vulnerable places, errors in code, design, security aspects, and so on. In general, testing helps to identify errors at early stages so that they do not turn into big problems in the future.

Software testing is a rather extensive part of work, so it is divided into several types. One of the most important types is software non-functional testing. Thanks to this stage, specialists manage to guarantee that the application meets the non-functional characteristics that were prescribed at the planning stage. In this topic, newcomers may encounter multiple nuances and pitfalls, so we have collected all the necessary information about testing non-functional aspects of a digital product for you.

Non-Functional Testing in Software QA – What is It?

It's no secret that a separate category of people - QA testers - are involved in testing a finished digital product. A large part of their work consists of detailed testing of non-functional parameters of a program or application. Simply speaking, they have to make sure that the software meets the pre-declared requirements of developers. The main points during non-functional testing are checking scalability, performance, security, and other parameters that are not directly related to the functional area.

Interestingly, the result of the developers' work depends on a lot of factors. If you want to increase your chances of successfully creating the necessary software, you should know how to choose the optimal technology stack. The right tools will save your development costs and finances.

Importance of Non-Functional Testing in Ensuring Software Quality

If you think that you can just ignore non-functional testing after the product is finished, this is not the case at all. Despite the fact that specific functional features are not tested during this phase, this type of testing is very important. Here's what it helps startups and development teams achieve:

Avoiding risks and unplanned costs. Obviously, the main benefit of checking non-functional aspects of software is cost reduction. This way, you can immediately identify vulnerabilities and fix them.
Improving performance. Such checks will allow you to improve the efficiency and performance of the application you have built.
Making sure that the product works comfortably. If your application works conveniently, it will help to increase the percentage of customer loyalty and improve behavioral factors.

In some cases, non-functional bugs and issues can cause the software to fail. If your product is poorly compatible, lacks scalability, and has poor security, it will be difficult to expect success.

Difference Between Functional and Non-Functional Testing

You know that software testing is divided into two categories – non-functional and functional testing. However, what is more important in the functional vs non-functional testing pair? Let's compare these two types of testing in detail.

Features of functional testing

This type of testing checks the basic functions of the program. In simple words, experts examine whether the software does what it is supposed to do. Imagine that you are working on developing a photo editing application. Hence, the main functions of this would be resizing photos, adding filters, etc.

Functional testing will check whether these functions are performed correctly and how much usability is involved. The aim and objectives of functional testing are to identify bugs and defects related to the functionality of the program.

Features of non-functional testing

This type of testing not only checks that a program does its main job but also evaluates its quality in terms of various aspects not directly related to its functions. Let's imagine we have a video streaming application. Its primary function is video playback. However, non-functional testing will evaluate other aspects, such as performance, security, and usability. The purpose of NFT testing is to check and evaluate software features that affect the user experience.

Types of Non-Functional Testing in Software Testing

As it was mentioned, this type of verification targets non-functional aspects. Do you want to explore this topic further? Experts usually distinguish five types of non-functional testing in software testing:

1. Performance

This type of testing checks how well a program performs under expected load and certain metrics. For example, you can test the response time of a web application when a large number of users access it at the same time. Usually, maximum performance capabilities are identified to understand how many users can use the program at the same time without any failures.

2. Load

Load testing is similar to performance monitoring. However, instead of users, the program's ability to accept other loads is examined here. This type of testing evaluates the program's ability to cope with extreme load conditions. For example, you can check how the program performs when a large number of transactions or database queries are executed simultaneously.

3. Security

Here, experts are focused on testing the program's vulnerabilities and its ability to protect data from unauthorized access or attacks. For example, you can conduct penetration tests to identify security weaknesses and protect them. This is one of the most important steps, as it will determine how secure your customers' data will be.

4. Usability

The next kind of testing focuses on testing how easy it is for users to use the program. What kind of real-world testing does this involve? For example, you can conduct usability testing to assess the understandability of the interface, ease of navigation, and how well the program meets users' needs.

5. Compatibility

Compatibility testing is just as important as all of the above. Why is it so? This test ensures that your product can easily match and integrate with other tools, platforms, or devices. For example, you can check if the app works properly on different devices, including PCs and smartphones.

Tools and Methodologies for Optimal Results

In the process of thorough software testing, you will definitely need third-party help. We mean non-functional testing tools that allow you to see weaknesses in performance, security, compatibility, and so on.

For security testing

OWASP ZAP has penetration testing tools which can be used to check the weak spots which are present in a web application. In dynamic environments, Burp Suite provides very advanced capabilities for identifying security flaws.

For performance testing

Application performance monitoring is crucial to keeping the users happy. New Relic gives real-time insight into application behavior to pinpoint bottlenecks. Transaction tracing and dependencies monitoring are where AppDynamics excels – they make sure transactions are healthy across different conditions.

For load testing

Apache JMeter is an extremely popular open source tool, which is used to simulate that heavily loaded servers, services, network and other resources. For high load scenarios, Gatling provides a developer friendly approach with powerful scripting.

For usability testing

Real-time feedback from real users catches usability problems well before your product goes live. An intuitive design of an interactive is ensured by the fact that Morae provides tools for recording and analyzing user interactions.

It would be very difficult to effectively verify non-functional software parameters without such tools.

Example of Non-Functional Testing in High-Traffic Applications

An interesting fact is that this type of testing should be done not only when you have just completed development but also when you are planning to deploy the program. Many global companies prove that you should regularly perform different types of non-functional testing. We have several examples:

Netflix. Netflix uses a non-functional testing framework to provide uninterrupted streaming to tens of millions of users. The platform simulates peak traffic during popular series releases, including scalability tests, which prove that servers can handle those surges without buffering or crashes.
Amazon. One of Amazon's main uses of load testing is to ready itself for events such as Black Friday or Prime Day. Amazon puts its software through extensive testing to confirm that its website is unable to respond properly.

Another example of this kind of testing is the famous social network Facebook (Meta). Facebook also periodically tests for security vulnerabilities to keep user data safe from breaches and cyber attacks. With billions of users, the platform is constantly being threatened, and it is vital to perform vulnerability scanning and penetration testing.

Final thoughts

If you study the experience of any software development company, you can understand that the non-functional testing stage is extremely important for the normal operation of the program in the future. It is as essential as knowing legal considerations when creating startups. However, you should not focus only on the non-functional features of the created software. You should also make sure that the application fulfills its main functions 100 percent and is useful for users.

Frequently asked questions

What are the main aspects of non-functional software testing?

This type of testing is characterized by the fact that it aims at checking important non-functional parameters. These include checking security, performance, compatibility, load and usability of the application.

What type of testing should be done first?

Generally, software development companies use their own approaches to testing created products. Usually, they pay attention to the functional part of the application first.

How long does it take to test non-functional parameters?

The time for testing non-functional aspects of a program can be different depending on the specific case. The time is affected by the size of the software and can take about a week for a complete check.