Functional Testing Vs Non Functional Testing- Two Useful Types of Testing

When it comes to successful project completion, testing plays a vital role. The software needs to be clearly understood by all involved and for this, functional and non functional testing are carried out. In the previous posts, we have talked about what is functional software testing and we also covered important aspects about non functional testing.

Both functional and non functional testing should be used in harmony and balance to achieve success. So, how these two types of testing are different from one another? Well, one of the most basic difference is that functional testing verifies a particular function of the code and on the other hand, non functional testing verifies aspects that are not associated with specific function such as security, speed or others.

Let’s get a detailed view about these types of testing with this comparison chart. This table has been laid out to point out the major differences between functional testing and non functional testing:

Functional Software Testing /
Functional Testing
Non Functional Testing
Basic Goal This type of testing is conducted to satisfy business requirements/specifications of the software application Non functional testing is conducted to satisfy clients’ requirements and performance of the software application
Types of Testing Types of functional testing: White Box Testing, Black Box Testing, Unit Testing, Integration Testing, System Testing, Regression Testing, Acceptance Testing, Smoke Testing, Sanity Testing Types of non functional testing: Load Testing, Stress Testing, Performance Testing, Volume Testing, Recovery Testing, Endurance Testing, Efficiency Testing, Security Testing, Scalability Testing, Usability Testing, Documentation Testing
Installation Testing, Configuration Testing
Compatibility Testing, Compliance Testing
Baseline Testing, Interoperability Testing, Maintainability Testing, Availability Testing, Recoverability Testing, Miscellaneous Testing
Priority Set This type of testing is implemented and practiced first in software testing It is the second level of testing conducted after functional testing
Impact Testing tells you about the core functioning of software application Testing tells you how good is the performance of the application
Input/Data Business requirements are treated as an input for the functional testing Performance parameters (Capacity, Scalability, Security, Usability, etc.) are treated as an input for the non functional testing
Suitable Environment Manual testing is best suited for functional testing Automation testing using automated tools is best suited for non functional testing
Detection of bugs and defects Testing can’t find all defects in the software application Testing can make software application bug free
Time Consumption Process of testing is time consuming Process of testing is less time consuming

So, these are a few basic differences between functional and non functional testing. While functional testing ensures that the system is working as per the functionalities specified in the business document, non functional testing checks the performance and reliability of the software system. Both types of testing have a pivotal role to play.
Which types of testing best suits your business requirements? Share your views with us in the comments!