While testing a software application, testers have to focus on both functional and non-functional requirements. They need to perform various types of functional tests to ensure that the software meets all business requirements. Likewise, they also need to assess the application’s user experience by performing a variety of tests against the non-functional requirements. That is why, it is important for the testers to understand some of the major differences between these two types of software testing.
5 Important Differences between Functional and Non-Functional Testing
As a type of black-box testing, functional testing is performed to check it the application meets all predefined business requirements and specification. The outcome of functional testing helps managers to decide if the software is ready for release. On the other hand, non-functional testing is performed to assess the application’s user experience. The testers perform a variety of tests against non-functional requirements to determine the amount of time required by the application to perform specific actions or respond to user request.
2) Types of Tests
A business has to perform both functional and non-functional testing to make the software popular and profitable in the longer run. So the testers need to perform usability, regression testing, smoke testing, and sanity testing to decide if the application is ready for release. At the same time, they also need to assess the application’s behaviour and user experience by performing a variety of non-functional tests like stress, load/performance, compatibility, reliability, compliance, and security testing. However, the types of functional and non-functional tests to be performed will differ from one project to another based on the nature and usage of the software.
3) Identifying Defects in the Software
Often the features and functionality of a software application is impacted by bugs, defects or flaws in it. These defects further prevent the software from meeting business requirements exactly and effectively. So the testers have to perform functional tests to identify the bugs or defects in the software, and get these eliminated without any delay. But the testers are not required to focus on finding bugs or defects in the software while performing non-functional testing. They have to perform tests against the application’s non-functional requirements to assess its behaviour and user experience.
4) Both Negative and Positive Testing
Normally, non-functional testing is performed based on a number of criteria that are not considered while performing functional testing. The tests performed against these criterions help testers to assess the quality of the software from the perspective of multiple users. But the testers have to perform both positive and negative functional testing. While performing positive functional testing, they have to submit valid inputs, and check how the application responds to these valid inputs accurately, and generate the desire outputs. Likewise, they also need to perform negative functional testing using invalid inputs, invalid operations, and unexpected operating conditions.
5) Test Automation Tools
An enterprise can automate both functional and non-functional testing efforts. In addition to reducing the testing time, the tools further help testers to perform the tests repeatedly. But often businesses find it easier to automate the non-functional testing. The testers can use a variety of tool to perform load, performance, stress and compatibility testing quickly and repeatedly. However, the testers have to write additional test scripts to perform both positive and negative functional testing through the tools. It is always important for the business to pick the right test automation tools to automate each type of testing effectively.
On the whole, the software testing strategy of a business has to focus on both functional and non-functional requirements of the applications. At the same time, it is also important for the testers to understand the objectives of each type of testing clearly to assess the software application more effectively.