White Box and Black Box Testing

When we talk about the Software Testing Process, then we know that we can test a software application only, when it is ready to test, that means when the developer has developed it, but before testing the software application directly, one need to test the code or the program which is written by developer, while building the software application. So, there are some levels of Testing, and in the first level of testing, the code of the application is tested, and then gradually Software Application is tested, and that’s where the concept of White Box and Black Box Testing comes into the picture, So We are going to see these concepts in this session.

Let’s understand the White Box testing first.

White Box Testing

What is White Box Testing

White Box Testing is made up of 3 words.
White+Box+Testing.
White – Let’s consider White Light
Box – Let’s consider a Box or you say a Glass Box.

If we spread or show a white light on the Glass Box, then we will be able to see inside the Box. We will be able to see the internal structure of the Box. We will be able to see the things that are kept inside the Box.

Now, If we assume this Box as a Software Application, and If you see inside a Software Application, then what can you see, You Can see the Codes or Programs written for the Software Application.

So, Therefore We can say that White Box testing is a type of Testing, Where the internal structure of the Software, or the code or programs written for the Software is Tested.

To Simplify the above statement, We can say that

White Box Testing is a type of testing where the internal structure of a software application, including the code and programs written for it, is tested. We can compare it to shining a white light on a glass box, which allows us to see inside the box and observe the internal components. Similarly, in White Box Testing, the focus is on analyzing the code and understanding how it functions to identify any issues related to code.

White Light gives us the visibility to see things, Same way, In White Box Testing, Tester will have visibility to the Code written for the Software. Now, We should be clear on one thing, tester will never have access to Code, then how can we say that tester will perform White Box Testing because In White Box Testing, tester need to access the Code, So one thing which is very clear is that only Developers will do White Box Testing.

1. White Box Testing is also called Glass Box Testing.
2. White Box Testing is also called Open Box Testing.
3. White Box Testing is also called Clear Box Testing.
4. White Box Testing is also called Structural Testing.

White Box Software Testing Technique

Here are some important White Box Testing Techniques

1. Statement Coverage
2. Decision Coverage
3. Branch Coverage
4. Condition Coverage
5. Path Coverage

Example of White Box Testing

Unit Testing – Whenever a Software is developed by a developer, then the developer develops it step by step. Module by Module. So, when 1 Module is developed, then that particular Module has to be tested independently, and that is called Module testing. Module is also component, So this testing is also called Component Testing. Component is also Unit, So this Testing is also Called Unit Testing.

We will discuss Unit testing in detail, in our coming sessions, but for now, We should know that Unit testing is a type of White Box Testing.

Advantage of White Box Testing

White Box Testing is the very first level of Software testing So Defects can be found at an early stage, If we perform White Box Testing.

Limitation of White Box Testing

1. We need to have knowledge of coding, programming in order to perform White Box Testing.
2. We can only find code related issues in White Box Testing because we test the code of the application.
3. We can’t find Configuration defects in White Box Testing.

Black Box Testing

What is Black Box Testing

Black Box Testing is exactly opposite to White Box Testing. In White Box Testing, We have access to the internal structure and the code of the Software Application, but in Black Box Testing, We don’t have access to the internal structure and the code of the Software Application.

We focus on testing the application directly in Black Box Testing. Our main focus is on testing the functionality of the Software Application.

We can understand Black Box Testing also the same way, We understood White Box Testing. Consider a Glass Box kept in a dark room, where there is no light, So We won’t be able to see inside the Box, We won’t be able to see the internal structure of the Box, and We won’t be able to see, what is kept inside the Box. So, If we consider the Software Application as a Box, then We can say that, In Black Box Testing, We don’t have access to the Code of the Application, We don’t have access to the Internal Structure of the Software Application. We directly test the application without having access to the code and the internal structure of the Software Application.

Black Box Software Testing Technique

Here are some important Black Box Testing Techniques

1. Boundary Value Analysis (BVA)
2. Equivalence Class Partitioning
3. Decision Table Based Testing
4. State Transition
5. Error Guessing

Example of Black Box Testing

Here are some important examples of Black Box Testing

1. Integration Testing
2. System Testing
3. User Acceptance Testing

Advantages of Black Box Testing

Here are some advantages of Black Box Testing

1. Black Box testing is done on the application directly, So We find the actual defects that might actually come in production.
2. We can find Configuration defects as well in Black Box Testing, which we can’t find in White Box Testing.
3. We don’t need to have Coding Knowledge, If we want to do Black Box Testing.

Limitation of Black Box Testing

We might miss some defects during Black Box Testing that are not related to functionality but are related to internal structure of the Software testing and can be found only during White Box Testing.

Difference between White Box and Black Box Testing

White Box Testing	Black Box Testing
White Box Testing is a type of Testing where we Test the Code of Software Application.	Black Box Testing is a type of Testing where we Test the Software Application Directly.
White Box Testing is done by developers.	Black Box Testing is done by Tester.
We can’t find issues related to Configuration in White Box Testing, We can only find Code related issues in White Box Testing.	We can find both Code and Configuration related issues in Black Box Testing.
One should have coding knowledge to White Box Testing.	No need to have Coding Knowledge to Black Box Testing.
White Box Testing is the very first level of Testing.	Black Box Testing is done after White Box Testing.

Summary

We have covered below topics in this session

1. What is White Box Testing
2. White Box Testing Technique
3. Example of White Box Testing
4. Advantages of White Box Testing
5. Limitation of White Box Testing
6. What is Black Box Testing
7. Black Box Testing Technique
8. Example of Black Box Testing
9. Advantages of Black Box Testing
10. Limitation of Black Box Testing
11. Difference between White Box and Black Box Testing

Question

List out the differences between White Box Testing and Black Box Testing.