Unit Testing Vs Functional Testing: A Guide On Why, What & How

  • Unit testing is performed by the developer during the development cycle, and
  • Functional testing is performed by the tester during the level of system testing.

What Is Unit Testing?

The Prime Objective Of Unit Testing Is:

  • To isolate a section of code.
  • To verify the correctness of code.
  • To test every function and procedure.
  • To find early bugs and fix in the development cycle and to save costs.
  • To help the developers to understand the code base and enable them to make changes quickly.
  • To help for code reuse.

Advantages Of Unit Testing:

  • Unit Testing allows developers to learn about the functionality that a unit provides. It also tells you how to use it to gain a basic understanding of the unit API.
  • Unit testing allows the developer to refine code and make sure the module works properly.
  • Unit testing enables testing parts of the project without the dependency of others for completion.

What Is Functional Testing?

The Prime Objective Of Functional Testing Is:

  • Finding defects that the programmer may have missed while developing software.
  • To Gain confidence and provide information about the level of quality.
  • To prevent defects.
  • To ensure that the result meets the business and the user’s requirements

Advantages Of Functional Testing:

  • Functional testing is necessary for evaluating the performance and the functionality of a software application before we deliver it to the client.
  • It takes the user’s perspective into consideration, which allows the software development team to create test scenarios that represent the real-world use scenarios.
  • It allows the team to meet the requirements of the user as well as the client.
  • It helps improve actual system usage.
  • It enhances the quality of the software product.

Difference Between Unit Testing And Functional Testing

Difference Between Unit Testing And Functional Testing

What Is The Purpose Of Both The Testing Types?

Unit Testing

Functional Testing

How Do Unit Testing And Functional Testing Improve Software Quality?

Unit Testing

Functional Testing


  • Unit testing is fast and helps writing clean code, but doesn’t provide confidence that the application will work as expected. It helps us where the problem/error is in the code.
  • Functional testing is slow and complex, but it ensures that the system will work as per the requirements. It helps us identify the problem/defects in the functionality.



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