The Fundamental Difference Between Functional and Non-Functional Testing
When it comes to software development, testing is an essential process. It helps in identifying and fixing any errors or issues in the software before its final release. However, there are various types of testing that developers use, and two of the most common ones are Functional and Non-Functional testing. In this article, we will dive deeper into the fundamental difference between these two types of testing.
Functional Testing
Functional testing, as the name suggests, tests the functionality of the software application. It focuses on verifying whether the software is performing as per the business requirements or not. Here, the testers test each functionality of the software application, ensuring its proper behavior, input values, and output values.
Some of the most common techniques used in functional testing are black-box testing, white-box testing, and gray-box testing. Black-box testing, also called behavioral testing, focuses on testing the software application without any knowledge of its internal structure or workings. On the other hand, white-box testing, also called structural testing, verifies the internal structures, code, and implementation of the software application. Finally, gray-box testing, which is a combination of both black-box and white-box testing, focuses on testing both the internal workings and external behavior of the software application.
Non-Functional Testing
Non-functional testing, on the other hand, tests the non-functional aspects of the software application, such as its performance, scalability, reliability, usability, and security. It doesn’t look at the functionalities, features, or business requirements of the software application. Instead, it focuses on the user experience and how well the software can meet non-functional requirements.
Some of the most common techniques used in non-functional testing are Load Testing, Stress Testing, Performance Testing, Usability Testing, and Security Testing. Load Testing verifies the software application’s ability to handle multiple users or transactions, Stress Testing checks how well the software application can handle sudden or unexpected loads, and Performance Testing ensures the software application’s performance under various circumstances.
Conclusion
In conclusion, functional testing focuses on verifying the software application’s functionality, while non-functional testing focuses on verifying its non-functional aspects. Both types of testing are essential for software development, and the selection of the type of testing depends on the software application’s requirements. As a developer, you need to understand these types of testing to ensure that you deliver high-quality software applications to your clients.
Table difference between functional and non functional testing
| Functional Testing | Non-Functional Testing |
|---|---|
| Involves testing the system against its functional requirements. | Involves testing the system against its non-functional requirements. |
| Tests the features, functionality, behaviors, and actions of the system. | Tests the system characteristics like performance, scalability, security, reliability, usability, and compatibility. |
| Tests are based on functional specifications, use cases, and user stories. | Tests are based on non-functional specifications and requirements. |
| Test cases focus on inputs, outputs, and workflows. | Test cases focus on system resources, response times, and user experience. |
| Functional testing is typically performed early in the software development lifecycle. | Non-functional testing is typically performed later in the software development lifecycle. |
| Functional testing is concerned with the correct functioning of the system. | Non-functional testing is concerned with the system’s performance, reliability, and security. |
| Examples of functional testing include unit testing, integration testing, and acceptance testing. | Examples of non-functional testing include load testing, performance testing, security testing, and usability testing. |