What is Unit Testing and Why it is done?

What is Unit Testing?

In software development designs, unit testing is a software testing type where the programmer tests each unit of source code against its specification.

A unit testing is nothing but a miniature testable part of a developed application. In procedural programming individual program, function, system, etc. can be viewed as util. In object-oriented programming, the miniature unit is a process, which may belong to a base/super class, abstract class or derived/child class.

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Each unit test case is viewed as an independent entity; to test one unit alone developed generally use stub, drivers, mock or false objects etc. Unit testing is done by the developing team to make sure the software is working as per the demand specification.

The objective of unit testing (sometimes referred to as module testing) is to:

1. Limit the extent of testing such that it is likely to find bugs in a humanly-manageable way.

2. Eliminate as many bugs as possible before integration testing begins.

3. Provide programmers with some real evidence of the worth of the units they have created by measuring it against either the specification from which it was coded or the harness and inputs which they have used.

Unit Testing Method

what is unit testing

Unit testing usually performed by using the White Box Testing method.

It is one of the techniques used in software testing. Sometimes it is suggested to as glass box testing, clear box testing, formative testing, and open box testing.

The white-box testing technique is usually achieved by running several tests in the application with the understanding of the internal working of the code base. It includes path to the source code to ensure the strength of a system in the face of malicious attacks or just easily the regular software breakdown. This testing is run based on the facts of how the method is put into practice.

When using this testing, the software tester should involve the review of data flow, the control flow, the data flow, coding practices, and exception and fault handling within the system. The purpose of this is to test the deliberate and intentional software behaviour. White box test cases must test various paths, decision points both in the true and false decisions, should perform loops, and verify internal data structures of the software.

When is it performed?

Unit Testing is the first stage of software testing life cycle process and is performed before Integration Testing.

System Integration Testing guarantees that all related processes exchange data seamlessly and supports a system’s ability to operate as needed with other systems within the same environment.

It includes testing of sub-systems collectively, to verify that they work well as a system. SIT majorly concentrates on whether data transfer between two or more systems is accurately received, stored and used while assuring that the system meets the requirements of the formal specification record as well as other generic requirements.

Unit Testing Benefits

Unit testing builds confidence in changing/ maintaining code. If real unit tests are written and if they are run every time any code is changed, we will be able to quickly catch any defects introduced due to the change. Also, if codes are already made less interdependent to make unit testing possible, the unintended result of changes to any code is less.

Development is active. How? If you do not have unit testing in place, you write your code and perform that obscure ‘developer test’ (You set some breakpoints, fire up the GUI, provide a few inputs that probably hit your code and hope that you are all set.) But, if you have unit testing in place, you sign the test, write the code and run the test. Writing tests takes time but the time is remunerated by the less amount of time it takes to run the tests;

Unit Testing Tips

  • Do not create test samples for everything. Instead, focus on the tests that affect the behaviour of the system.
  • Separate the development environment from the test environment.
  • Use test data that is near to that of production.
  • Before settling a defect, write a test that shows the defect. Why? First, you will later be able to find the defect if you do not fix it properly. Second, your test line is now more complete. Third, you will most presumably be too lazy to write the test after you have already fixed the defect.
  • In addition to writing cases to support the behavior, write cases to ensure the execution of the code.

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