Are Non-functional requirements difficult to test and hard to express?

Yes, Non-functional requirements are not bothering about the user-given requirements (SRS) or the functional requirements. It mostly focused on the quality and behaviors of the software. So, we can’t measure the quality and behaviors. That is why they are more difficult to test and express.

In non-functional testing, the performance or behaviors of the application is focused. And also quality attributes like usability, efficiency, security, scalability, portability will be focused on. All those non-functional facts are difficult to measure and a bit hard to test and verify the requirements. Non-functional requirements are nice to have in the application, not a must.

If I take the example from security testing, suppose there may be some security issue or confidential leakage in the system. So we have to make sure how well the confidential data and internal resources are protected and have to find the system’s vulnerabilities. It may be very hard to test and verify.

And also there may be few users and resources in the team but we are giving our system to a huge client base. So we need to make sure our system is capable of working with the huge community simultaneously without any interruptions. For the small companies, it will be difficult to manage.

When it comes to performance testing, when we do the load testing (performance) to the application, we need more users and resources. So it may be very difficult for some small companies or teams. And also there may be network failures or delays when we do the testing. Then we can’t guarantee, that software reaches the user’s requirements or not.

Likewise, there may be several barriers when testing the non-functional requirements.

Originally published at https://www.linkedin.com.