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13 Types of Software Functional Testing

13 Types of Software Functional Testing

In software testing, functional testing is used to verify the functionality of a software application, to check whether each function is working according to the requirement specifications. It is a practice that delivers huge benefits to software development processes.

Software testing in itself is the process of analyzing a software product to identify defects or errors and to evaluate the features of the software as well as verify that a software product or application does what it is supposed to do.

Functional testing is one of the 3 core types of software testing, others include non-functional and maintenance testing. Each of these core testing handles different aspects of a software application and one cannot replace the other.

What is Software Functional Testing?

This type of software testing involves the testing of the functional aspects of a software product where each and every functionality is tested to see whether it matches the desired results or not. This type of testing seeks to establish whether each application feature works in line with software requirements.

This type testing is done by providing sample inputs, capturing resulting outputs, and verifying that the resultant outputs are the same as the expected outputs. Each function is compared to a corresponding requirement to ascertain whether its output is consistent with the end user’s expectations.

13 Types of Software Functional Testing

  1. Unit testing

A unit is a single testable part of a software system or a unit component of an individual function or code of the application. Unit testing is a practice where individual unit of a software product code are tested to determine whether they are fit for use. The purpose of unit testing is to test the correctness of isolated code.

  1. Module testing

An application can be thought of a combination and integration of many small individual modules. Module testing (also called component testing) tests each module of the system individually where they each receive an input, does some processing and generates the output, then the output is then validated against the expected result.

  1. Smoke testing

This is a type of acceptance testing that checks whether new or critical functionalities meet their objective. It is also called build verification testing, which is done after each build is released to ensure build stability.

  1. Sanity testing

This is usually done after smoke testing and it verifies that every major functionality of an application is working perfectly.

  1. System testing

This a testing type is done on a complete system to verify if it works as expected once all the modules or components are integrated.

  1. White-box testing

This is when the software’s internal infrastructure, code and design are visible to the developer or tester. Generally white box testing focuses on testing the code itself, it therefore requires programming knowledge.

  1. Black-box testing

This kind of testing is often done by testers who have little to no programming knowledge. This method is used to validate expected outputs against specific inputs.

  1. Alpha testing

It is a type of acceptance testing that is perform to identify all possible issues and bugs before releasing the final product to the end users. This is done by internal team members

  1. Beta testing

This is performed by ‘real users’ of the software application in ‘real environment’. It is the final test before shipping a product to the customers which help get feedback from unbiased users who may perhaps identifying critical unknown bugs before release to a wide user base.

  1. Regression testing

Regression testing helps maintain a stable product while changes are made to it. It is done to ensure that changes to codebase (new code, debugging strategies, etc.) do not disrupt the already existing functions or trigger some instability.

  1. Integration testing

This type of software functional testing that verifies if individual modules of code work properly as a group. It validates that the end-to-end outcome of a system meets the necessary standards.

  1. API testing

Application programming interfaces (API) connect different applications or systems. API testing helps validate that API connections and responses function as intended, like how they handle data and user permissions.

  1. UI testing

UI testing includes testing of user interface controls like buttons, menus and text input to ensure that the experience flow and features chosen are optimal for single or multiple user experience.


Functional testing is one of the important testing processes as it verifies the functionality of a product. At Podtech, we understand that functional testing plays a crucial role in ensuring that clients’ software requirements are optimally satisfied.