Unit Testing Vs Functional Testing: Difference Between Unit Testing and Functional Testing

Unit Testing Vs Functional Testing: Difference Between Unit Testing and Functional Testing

Unit Testing Vs Functional Testing: Difference Between Unit Testing and Functional Testing

As the title suggests, it is not only about choosing one between Unit testing and Functional testing for software development, the blog will cover much more. As a matter of fact, you will see in the blog that both software testing types have their own importance in software development, and have their own advantages as well as limitations. However, there are different contrary opinions about both the testing types. Thus here we have compared Unit Testing Vs Functional Testing.

To put it another way, the ultimate aim of any software testing is to provide a quality product. Another key point of the foundation of the testing process is Unit and Functional testing. Generally speaking, the major difference between the two software testing types is:

  • At the time of the development cycle, the developer performs the Unit testing, and
  • The tester performs the Functional testing at the level of system testing in software development.

with this in mind, you will get to know several such differences through this blog. With this in mind, the blog post aims to make you understand the different aspects of both software testing types. Moreover, this blog post will cover the parameters like the objectives of both types of testing, benefits of each software testing type, differences, and other valuable information. So, stay tuned!

What is Unit Testing?

Unit Testing Vs Functional Testing

Unit testing is a well-liked practice embraced by lots of organizations because of the reason that it first and foremost helps to get rid of bugs in code risk. In simple words, unit testing is a software testing type where individual units or components are tested. The primary purpose of unit testing is to validate software codes for each unit and find out if they are performing as per the expectations.

The ultimate aim of unit testing is to break source codes’ every part into the unit and see if each part works appropriately. That signifies if any set of input is not functional, return output is expected.

What is the Objective of Unit Testing?

Let’s see the prime objective of Unit testing:

  • It tests the units of code in isolation.
  • It verifies if the code is correct.
  • It tests each function as well as procedure.
  • It detects bugs earlier and fixes them in the development cycle simultaneously saving cost.
  • It helps in understanding the code-base by the developers and allows them to quickly make changes.
  • It also assists in code reuse.

Benefits of Unit Testing

  • Unit testing enables developers to know about the functionality provided by a unit. Additionally, explain to you the way of using it for gaining a basic understanding of the unit API.
  • Unit testing enables the developer to refine code and ensure the working of the module is appropriate.
  • Unit testing allows testing of the project’s parts without relying on others for the purpose of completion.

What is Functional Testing?

Unit Testing Vs Functional Testing

Functional testing is a process of software testing that substantiates the software system in opposition to functional specifications. Testing every functionality of software application is the purpose of functional testing which is done by providing appropriate input and output verification against the functional specifications. In simple words, functional testing is a type of testing in which the system is tested in opposition to the functional requirements or specifications.

What is the Objective of Functional Testing?

  • It detects the defects that might be missed by programmers while developing software.
  • It helps in gaining confidence and delivers information regarding the level of quality.
  • It ensures the outcome that meets the business and the user’s expectations.

Benefits of Functional Testing

  • Functional testing is very essential for the evaluation of performance and the functionality of a software application before delivering it to the client.
  • Considering the user’s perspective enables the software development team to build test scenarios representing the real-world use scenarios.
  • Enabling the team to meet all the requirements/demands of the user and client both.
  • This types testing helps in improving the actual system usage.
  • The quality of the software product is enhanced with the use of Functional testing.

Differentiating Factors to Consider Between Unit Testing and Functional Testing

Let’s have a look at the factors mentioned below that will help you in understanding the role of Unit testing and Functional testing in the software or application testing process.

Factors Unit testing Functional testing
Definition and purpose Testing the units of code in isolation Testing the functionality as per user requirements
Written by Developers Tester
Complexity Easy to write and execute More complex comparatively
Testing techniques White-box testing Black box testing
Errors covered Code branches, edge cases Software/app functionality
Cost and maintenance Low High
No. of test cases Higher than any other testing Lower than unit and integration testing
Changes Changes frequently Low rate of changes

FAQs Unit Testing Vs Functional Testing

Wrapped Up

Distinguishing between the intent and scope of Unit tests vs Functional tests is very essential for Developers and Testers. For the reason that both the tests are used for different purposes or objectives, both aren’t interchangeable. As both Unit tests and Functional tests have their own benefits and drawbacks or limitations.

Unit testing is quick and assists in writing clean code yet don’t give confidence if the system will work as per the expectations. Fundamentally, it assists in detecting the problem in the code.
On the other hand, Functional testing is slow and complex even though it makes sure that the system will work as per the requirements. Primarily, it tells about the problem in the functionality
Eventually, the testing aims to provide a quality product.


Kush P

Kush Patel is the Chief Technical Officer and Managing Director of Echo Innovate IT – a software development company. He is responsible for the overall operations of the company and has played a major role in making Echo innovate IT the top-notch IT services provider and transforming it into a globally trusted web and app development company.

Leave a comment

Your email address will not be published. Required fields are marked *