Key Differences Between Black Box Testing and White Box Testing

A Thorough Study of Black Box Testing Vs White Box Testing:

Software testing includes several types of testing and as a software tester, we must know how each of them is performed.

Among the various types of testing, one of the most confusing topics is that of the Black box Vs White box testing. Many software testers wonder if there is any similarity between these two types of testing. How are they both performed? Are they both performed together?

This document will answer all your questions and give you a basic idea of what black box testing and white box testing are and explain the differences between them in simple terms.

black box vs white box testing

What Is Black Box Testing?

ISTQB Definition – Black Box Testing: Testing an Application Under Test (AUT) without referencing the internal structure is called the black box testing. Testing will be done by visualizing the application as a black box.

Black Box Test Technique: A testing technique to derive the test cases based on the functionality of the application and not considering the internal structure of the system.

Synonyms: Specification-Based Testing

black box testing

Black box testing is a testing approach that is used to test the functionality of the AUT based on the specifications/SRS without any knowledge of the technology used to implement the application under test.

In the black-box testing, major testing will be around possible inputs and expected outputs. A tester should be able to choose the valid test data carefully. In simple terms, a tester can only see the actions of the AUT. The tester need not know how those actions are performed.

Example: A simple example of black-box testing is a TV (Television). As a user, we watch the TV but we don’t need the knowledge of how the TV is built and how it works, etc. We just need to know how to operate the remote control to switch on, switch off, change channels, increase/decrease volume, etc.

In this example,

The TV is your AUT (Application Under Test).
The remote control is the User Interface (UI) that you use to test.

You just need to know how to use the application.

Suggested Read => All That You Need to Know About Black Box Testing

What Is White Box Testing?

ISTQB Definition – White Box Testing: Testing an application with reference to the internal structure of the software component is called white box testing.

White-box test technique: A Procedure to derive and/or select test cases based on an analysis of the internal structure of a component or system.

Synonyms: Clear-box testing, Code-based testing, Glass-box testing, Logic-coverage testing, Logic-driven testing, Structural testing, Structure-based testing, etc.

white box testing

White box testing is a test approach that is used to test the implementation part of an application under test. To perform this testing, the tester/possibly the developer should know the internal structure of the application and how it works.

Example: A Car mechanic should know the internal structure of the car engine to repair it.

In this example,

CAR is the AUT (Application Under Test).
The user is the black box tester.
The mechanic is the white box tester.

These are the basic definitions of white and black box testing and each test method has different techniques to follow.

Recommended Read => An In-Depth Tutorial on White Box Testing

Difference Between Black Box and White Box Testing

S.NoBlack Box TestingWhite Box Testing
1The main objective of this testing is to test the Functionality / Behavior of the application.The main objective is to test the infrastructure of the application.
2This can be performed by a tester without any coding knowledge of the AUT (Application Under Test).Tester should have the knowledge of internal structure and how it works.
3Testing can be performed only using the GUI.Testing can be done at an early stage before the GUI gets ready.
4This testing cannot cover all possible inputs.This testing is more thorough as it can test each path.
5Some test techniques include Boundary Value Analysis, Equivalence Partitioning, Error Guessing etc.Some testing techniques include Conditional Testing, Data Flow Testing, Loop Testing etc.
6Test cases should be written based on the Requirement Specification.Test cases should be written based on the Detailed Design Document.
7Test cases will have more details about input conditions, test steps, expected results and test data.Test cases will be simple with the details of the technical concepts like statements, code coverage etc.
8This is performed by professional Software Testers.This is the responsibility of the Software Developers.
9Programming and implementation knowledge is not required.Programming and implementation knowledge is required.
10Mainly used in higher level testing like Acceptance Testing, System Testing etc.Is mainly used in the lower levels of testing like Unit Testing and Integration Testing.
11This is less time consuming and exhaustive.This is more time consuming and exhaustive.
12Test data will have wide possibilities so it will be tough to identify the correct data.It is easy to identify the test data as only a specific part of the functionality is focused at a time.
13Main focus of the tester is on how the application is working.Main focus will be on how the application is built.
14Test coverage is less as it cannot create test data for all scenarios.Almost all the paths/application flow are covered as it is easy to test in parts.
15Code related errors cannot be identified or technical errors cannot be identified.Helps to identify the hidden errors and helps in optimizing code.
16Defects are identified once the basic code is developed.Early defect detection is possible.
17User should be able to identify any missing functionalities as the scope of this testing is wide.Tester cannot identify the missing functionalities as the scope is limited only to the implemented feature.
18Code access is not required.Code access is required.
19Test coverage will be less as the tester has limited knowledge about the technical aspects.Test coverage will be more as the testers will have more knowledge about the technical concepts.
20Professional tester focus is on how the entire application is working.Tester/Developer focus is to check whether the particular path is working or not.

Conclusion

White box and black box testing are necessary for the successful software delivery but 100% testing is not possible in either of the cases.

The major responsibility of the tester is to identify the relevant test types and techniques for a specific application which will result in finding maximum defects and thereby improving the efficiency of the application.

A tester should be able to identify how much testing can be done either in the black box or in the white box testing to certify that an application is working as expected.

We hope this tutorial clarified all your queries on the Black box Vs White box testing!!