Functional Testing

Functional testing is a part of the software testing process which checks the functionalities of the product on various levels and makes sure that the product is performing according to the requirements of the users, is free of bugs and errors, and determines the product’s credibility.

There are various kinds of techniques for functional testing that test out different areas and functions of the software using functional testing tool/tools and ensure a high-quality product. The different functional testing techniques are as mentioned below: 

Unit Testing

Unit testing is an example of automated testing where you write a code and test out a small portion of it to see if the code is functioning as you want it to. This testing technique is to verify the individual functions or classes or anything of small size.  

Read More:- Why System Testing is Important in the Testing Cycle?


  • It is helpful in writing better software codes.
  • Identifying bugs becomes easy using the unit testing technique early
  • Regression bugs can be easily detected with this technique
  • The unit testing technique helps refactor the codes
  • You can write better codes using this technique  


  • Even though writing codes has become easy, it takes you more time to write them
  • Writing tests for the legacy codes is difficult in unit testing technique
  • A lot of maintenance is required for this testing technique
  • Conducting a test on GUI codes can be really hard
  • All the errors can not be identified using this testing technique

Integration Testing

Integration testing is the technique of verifying if the particular modules of the software in which integration of one or more applications occurred are working as they were supposed to and meet the users’ requirements. This testing technique ensures that the applications communicate and assimilate well with each other.  


  • It offers a systematic approach for testing out the communication and assimilation of the applications
  • Integration testing provides a methodical approach for assembling system applications
  • It helps detect the bugs and errors associated with interfacing
  • It ensures that the test meets the standards and demands set by the users
  • Integration testing makes sure that the assumptions made by developers were correct or not


The integration testing technique is carried out using different approaches that are the Big Bang approach and the Incremental approaches, the Top-Down approach, the Bottom-Up approach, and the Sandwich approach, and all of them have their respective disadvantages. 

  • In the Big Bang approach, fault localisation is tough, and some interface links can easily be missed to be tested, etc
  • In integration testing, the main con is, time-consuming.

User Acceptance Testing

User acceptance testing (UAT) is a type of acceptance testing and functional testing technique. As the name suggests, user acceptance testing checks out the acceptability of the software and that it is working well for the users. This testing technique is conducted using the black-box testing approach in which the internal codes are hidden and do not need programming language knowledge. 

In the user acceptance testing technique, real-end users participate in the testing and check the functionality of the product and no development team takes part in the testing process.


  • The product is tested out by the real-end users themselves, and they detect the errors.
  • Due to no involvement of the development team in the testing process, the test outcome is unhindered and raw.
  • It does not require high programming knowledge to conduct this test
  • Due to the black-box testing approach, all the functionalities are covered in the testing process
  • It increases the trust in the users for the product


  • Not all the users participating in the testing process have knowledge of the product
  • All the users don’t participate in the process
  • There are various opinions and thus takes a lot of time to evaluate the outcome of the test


We have discussed three functional testing techniques in this post, the unit testing technique, the integration testing technique and the user acceptance technique. All these testing techniques check the functionalities of the product, but on different levels.

By Payal Goyal

"Payal Goyal is the Sr. Seo Executive with a passion for blogging. She is a good content writer. Her passion, dedication and quick decision making ability make her stand apart from others."

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