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Unit Testing for Application Softwares.

Unit Testing for Application Softwares.

31 August 2022 4 MIN READ BY Rajesh K

Table of Contents


What is Unit Testing?

A unit is the smallest piece of code that can be logically isolated in a system. It may be an individual function, method, procedure, or a module. Units are the smallest testable parts of an application software. Unit testing is a part of software testing.

  • We explore units separately to identify issues. Its primary purpose is to validate each unit independently against its purpose or performance.
  • Software developers and sometimes QA staff perform this type of testing during the development process of an application software.


Advantages of Unit Testing

The main advantages are,

  • Software developers and software testers familiarize themselves with the functionality provided by a unit and how to use the unit. It also helps them to acquire a basic understanding of the unit API.
  • Unit testing allows the software developer to manipulate the code to ensure the proper functioning of a module. This improves code quality.
  • It enables testing parts of the project without waiting for the completion of the whole project.
  • We capture and rectify defects in the very early phase of the project, which saves much testing time later.


Unit Testing Process

We can brief the steps as follows.

  • Create test cases: – Identify a unit test corresponding to the relevant feature to be tested. The software developer writes a section of code in the application to facilitate this. The software developer would later comment out and finally remove this section of code when deploying the application.
  • Reviewing test cases: – The section of code to be tested is isolated to a separate testing environment. This helps in exposing unwanted dependencies between the code being tested and other units. We can then remove these dependencies.
  • Baselining test cases: – Software developers make use of Unit testing frameworks or  tools for handling automated test cases.
  • Executing test cases: – During the execution of test cases corresponding to unit testing, the framework helps to mark the test cases that fail and also helps in reporting those failed test cases. The framework further helps to stop the related testing in case of failures.


Testvox Software Testing Company


Unit Testing Methods

There are two ways to perform this type of testing.

  • Manual Testing: –

The software tester manually executes each step of a test case and does not require to know about any testing automation tool. Manual Testing is tedious especially for tests that are repetitive and have many steps.

“100% of Automation is not always possible and so there is always room left for some level of manual testing to be done.”

  • Automated Testing: –

Software testing automation tools automate and store the test cases to be executed. The automation tool records and saves the steps entered in test cases, and can replay them as many times as required.

“The automation tool can even compare the expected results to the actual results and automatically generate the reports.”



Software testers utilize three types of techniques while testing each unit separately. 

  • White Box Testing: –This testing requires an in-depth knowledge of the program’s internal code structure   to ensure it is performing its intended function and to examine how it does so.

“Unit testing is a type of white box testing where the software developer inspects the lines of code to be tested to point out bugs in the earlier phase of the development process.”  

  • Black Box Testing: – In this type of testing, software developers test the functionalities of an application software without possessing any knowledge about its internal code structure. The aim is to ensure accurate and efficient execution of the functionalities. The software testing team derives these tests from the software specification document.
  • Grey Box Testing: – The grey box testing is a combination of black box and white box testing techniques. The testers possess only limited knowledge about the internal code structure of the application software to be tested. This type of testing aims to identify bugs resulting from improper code structure or incorrect code.



Unit testing ensures the efficiency of the performance of all the individual units of the application software in its developmental phase. Detecting bugs and rectifying them during this type of testing saves time and money rather than the testing done at the later stage of software development. Software testing tools can automate test cases corresponding to unit testing, which is a good idea. You can use a software testing framework to develop and maintain these test cases.

Rajesh K

Possessing Post Graduation in Applied Electronics with a specialization in Microprocessors and embedded systems, I started my career as a faculty in computer applications. Shifted to IT industry after few years and worked as a Quality Analyst for almost 7 years.