What is the Difference Between Unit Testing and Functional Testing

The main difference between unit testing and functional testing is that the unit testing checks the individual modules or units of the system while the functional testing checks the features or the functionalities of the system.

Software testing is a major functionality in software development. It helps to provide working and reliable software to the customers. There are various types of testing, and unit testing and functional testing are two of them. Unit testing ensures that the units or modules of the system work properly. On the other hand, functional testing verifies that the system is tested against the functional requirements or specifications.

Key Areas Covered

1. What is Unit Testing
     – Definition, Functionality
2. What is Functional Testing
     – Definition, Functionality
3. What is the Relationship Between Unit Testing and Functional Testing
     – Outline of Association
4. What is the Difference Between Unit Testing and Functional Testing
     – Comparison of Key Differences

Key Terms

Unit Testing, Functional Testing

What is Unit Testing

Unit testing is a type of testing that checks whether individual modules work properly. It checks whether each standalone module works correctly. The aim of this unit testing is to isolate every module in the system and to test each of them separately.

For example, assume a Library management system. The system administrator should log in to the system to operate the system. He should enter valid username and password to enter the system. Therefore, checking whether the login modules work properly is an example for unit testing. In general, developers perform unit testing.

What is Functional Testing

Functional testing is a type of testing that ensures that software is working according to the specified requirements. It involves testing all the main functionalities of the software. Moreover, the software tester can use various inputs to check the corresponding outputs. He can compare the actual results with the expected results. Functional testing also involves testing the user interface, database, etc.

For example, assume a Library Management system. This system has various functionalities such as Login, add new member, update member, add book, update book, search book, view book details, borrow book, return book, view member details, search member and late fee payment. Therefore, functional testing involves testing all these functionalities to check whether each of them works as expected.

Relationship Between Unit Testing and Functional Testing

• Unit testing is a type of functional testing.

Difference Between Unit Testing and Functional Testing

Definition

Unit testing is a level of software testing where it tests individual units of a software. In contrast, functional testing is a software testing process used within software development where it tests the software to ensure that it conforms to all requirements. Thus, this is the main difference between unit testing and functional testing. 

Main Functionality

Another difference between unit testing and functional testing is that the unit testing checks the functionality of individual modules or units while the functional testing checks whether the system works according to the requirements.   

Conclusion

The main difference between unit testing and functional testing is that the unit testing checks the individual modules or units of the system while the functional testing checks the features or the functionalities of the system. In brief, unit testing is a type of functional testing.

Reference:

1. “Software Test Types” TutorialRide.com, Available here.
2. “Levels of Software Testing”, TutorialRide.com, Available here.

Image Courtesy:

1. “Testing With Magnifier” (Public Domain) via PublicDomainPictures.net