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Functional Testing Vs Non-Functional Testing

In previous articles we have seen separate articles for Functional Testing & Non-Functional testing. But in today’s article we will see the actual difference between Functional Testing Vs Non-Functional Testing.

What is Functional Testing?

Functional Testing is the type of testing done against the business requirements of application. It is a black box type of testing.

It involves the complete integration system to evaluate the system’s compliance with its specified requirements. Based on the functional specification document this type of testing is to be carried out. In actual testing, testers need to verify a specific action or function of the code. For functional testing either manual testing or automation tools can be used but functionality testing would be easier using manual testing only. Prior to non Functional testing the Functional testing would be executed first.

Five steps need to be keeping in mind in the Functional testing:

  1. Preparation of test data based on the specifications of functions
  2. Business requirements are the inputs to functional testing
  3. Based on functional specifications find out of output of the functions
  4. The execution of test cases
  5. Observe the actual and expected outputs

To carry out functional testing we have numerous tools available, here is the list of Functional testing tools.

In the types of functional testing following testing types should be cover:

What is non Functional Testing?

The non Functional Testing is the type of testing done against the non functional requirements. Most of the criteria are not consider in functional testing so it is used to check the readiness of a system. Non-functional requirements tend to be those that reflect the quality of the product, particularly in the context of the suitability perspective of its users. It can be started after the completion of Functional Testing. The non functional tests can be effective by using testing tools.

The testing of software attributes which are not related to any specific function or user action like performance, scalability, security or behavior of application under certain constraints.

Non functional testing has a great influence on customer and user satisfaction with the product. Non functional testing should be expressed in a testable way, not like “the system should be fast” or “the system should be easy to operate” which is not testable.

Basically in the non functional test is used to major non-functional attributes of software systems. Let’s take non functional requirements examples; in how much time does the software will take to complete a task? or how fast the response is.

Following testing should consider in non functional testing types:

  • Availability Testing
  • Baseline testing
  • Compatibility testing
  • Compliance testing
  • Configuration Testing
  • Documentation testing
  • Endurance testing
  • Ergonomics Testing
  • Interoperability Testing
  • Installation Testing
  • Load testing
  • Localization testing and Internationalization testing
  • Maintainability Testing
  • Operational Readiness Testing
  • Performance testing
  • Recovery testing
  • Reliability Testing
  • Resilience testing
  • Security testing
  • Scalability testing
  • Stress testing
  • Usability testing
  • Volume testing

To get software testing articles in your inbox click here to Subscribe with your email address link. Also I would like all of you to please join this discussion and add more valuable points to it. Thanks.

17 comments to Functional Testing Vs Non-Functional Testing

  • mahesh


  • venkatesh


  • Shashank

    here i understand the actual different b/w fcnl & non fcnl testing.

  • Sudhir

    Wow!!! Excellent…

  • Sv

    Great! But why usability testing is in-both: functional and non-functional testing?

    • sw test

      @Sv – it’s not. Usability testing is non functional.

  • Nanda

    If Functional Testing is considered as blackbox testing, then why Unit Testing comes under it. Unit testing is considered as white box testing type.

    And Couldn’t understand that, is System Testing Will be only under Functional Testing?

  • RK

    Very Easy To Understand……

  • Nidhi

    Easy to understand

  • HieuPham

    – Functional Testing is a Black box type of testing.
    – Unit testing is type of functional testing.
    – Unit Testing is performed by using the White Box Testing method.
    >> seem turbid, Could you explain for me?

  • @bhi

    well explained..

  • Hanuman Reddy

    Great Informative

    We request you provide some more information about Manual Testing as well as SDLC models.

    Your explanation is fantastic and awesome

  • Neha

    It is so good information

  • Nikunj Pitroda

    So nice and easily understanding language for learn.

  • Rachana

    Appreciated your efforts, keep up the good work.

  • Archana

    Can you please share the information on “Localization testing and Internationalization testing”?

  • Sachin Kothawade

    its very nice information
    helpful for everyone

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