Functional Vs. Non-Functional Testing: What Differentiates the Two?

In any software development, there are different processes involved. Among them, one of the most important processes is testing. This is the process that assures the satisfaction of the customers. Also, there are certain standards and requirements for the software and the testing process needs to confirm this stage as well. Testing involves two types, one will be functional and the other is the non-functional testing. These types of testing are different – continue reading to learn about both of them.

Things About Functional Testing

As the name denotes, every function of the software can be defined by using functional testing and it confirms with several other specifications required for the process. The functional testing is all about the black box testing but not about the source code testing.

Each functionality of the system will be provided with the appropriate input and verifies the output. Later, it finalizes the results by comparing obtained results to the expected results. This can be done by some processes like interface, clients/ server application, security, database, and the functionality of the application that is considered under the testing. Also, this test can be done both manually and automated.

Non-Functional Testing

Non-functional testing is the type of testing that is used to check only the non-functional units of the software application that includes performance, reliability, usability, etc. This type of testing is designed particularly for enhancing the readiness of the system. Also, certain non-functional parameters will not be addressed by functional testing.

To explain with the best example, it can be demonstrated by the ability of the people to access the software simultaneously. It is considered equally significant as the other type of testing and it also affected the satisfaction of the client.

Key Differences Between Functional and Non-Functional Testing

Although the functional and the non-functional units perform their functions for delivering the best software for the clients and to improve the quality of the software, there is a difference in the testing. Continue reading to learn some of the significant differences.

• The functional system will be responsible for representing how well the system can work but the non-functional will take care of how the software responds. For example, if the functional testing will test the mechanism of the input data, the non-functional testing will work on testing the speed at which each document will be saved.
• Functional testing will address the customer’s requirements, but the counterpart will be based on the expectations of the customers. Now, modern business shows a great difference between the expectation and requirements of the clients. This can be faced and met only with the help of non-functional testing.
• Customer feedback has greater value for non-functional testing. Though the functional testing benefits more directly with the feedback, the non-functional testing gains more insight with it. It is because it will allow the testers to know the customers’ expectations and the impacts on their products.
• It is not easy to conduct a thorough and efficient non-functional testing process without appropriate tools. This is not as big an issue in the case of the functional testing as it can be done easily with manual testing as well.
• The other major difference can be stated as the nature of the requirements on which the tests are based. The functional requirements will specify the functionality that needs to be tested and the non-functionality will test how they will need to be tested. Also, the implementation of both will require tests performed in separate places. The functional requirements are defined in the system design; the non-functional requirements will be defined in the architecture of the system.
• For an easy understanding of both the systems, you can go through a better example. Under functional testing, it is possible to test if providing the username and password on the log-in screen will allow the user to log in to the site. For the non-functional testing, you can check if the user will be able to log in to the site within 3 seconds by providing the username and password.

Final Takeaways

For any software testing, non-functional testing will be crucial. There cannot be any testing process completed without such testing. It ensures the application or product behavior is acceptable and completely in line with requirements for the business.

Such non-functional testing will need strategizing and planning. If needed, you can include some non-functional testing details in the overall test plan or alternatively devise a unique plan for it. Either way, the final result will cover all the non-functional aspects of the comprehensive software concerns.