Black Box Testing vs White Box Testing: Know the Key Differences

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Black Box Testing vs White Box Testing: Know the Key Differences

Recently Microsoft was in the news for awarding a 20-year-old Delhi-based ethical hacker Aditi Singh with INR 22 lakhs for discovering an RCE bug in Microsoft's Azure cloud system. For those who are wondering the reason why this IT giant rewarded her heavily, tiny bugs in software products can lead to huge losses if not tested duly. When a software project is on its way to completion, testing is the most important part of it. One needs to make sure that errors don’t appear in any phase and if it happens so, it is identified and corrected timely. Software testing is the process of evaluating and verifying that a software product is free of bugs and errors and performs the tasks expeditiously. A proper testing of software can ensure security, efficiency and high performance. It is also important as it increases brand value by providing good quality products that are cost effective. Software testing can be done using numerous methods and techniques. However, in this article we will focus on Dynamic Testing.

What is Dynamic Testing?

Dynamic Testing is a type of Software Testing which is used to examine the dynamic behaviour of the code. Dynamic testing is primarily used to detect those defects that can't be detected by static testing. It detects security threats and ensures a better quality of the software product.

Testing is majorly done in two parts. Also known as the 2 Vs,

Verification (static testing)
Validation (dynamic testing)

Levels of Dynamic Testing

There are various levels of Dynamic Testing such as:

Unit Testing
Integration Testing
System Testing
Acceptance Testing

Dynamic testing can be classified into two categories:

White Box Testing
Black Box Testing

What is White Box Testing?

White Box Testing is a software testing method in which the internal structure or design along with the workings is known to the tester. It is also known as glass testing or open-box testing. White Box testing is performed to check whether the system is functioning well based on the internal logic. Sometimes, due to advanced modifications the existing code doesn’t work. In that scenario, engineers use this technique to ensure that the system as a whole is not damaged.

Types of White-box testing:

Path Testing
Loop Testing
Condition testing

Let’s have a look at the advantages and disadvantages of white-box testing –

Advantages	Disadvantages
It identifies errors in code and thus makes the debugging process easier.	Since a skilled tester is required for conducting white-box testing, it is costly.
It removes extra lines of code that are not required in the program. Hence, optimization of the program becomes easy and efficient.	It is not considered feasible for the testing of large applications.
It helps in evaluating all the loops within the program.	It is an exhaustive process and requires a highly skilled tester.
Various hidden defects are revealed while performing white box testing.	Sometimes, appropriate test cases take longer time to develop, making it time-consuming.
As we already have the knowledge of the source code, tester can make the testing process more efficient with appropriate test cases.	Any small change in the code can lead to testing again from scratch.

What is Black-Box Testing?

Black box testing is the technique of software testing in which the code is tested without having any knowledge of the internal working of the application. It is also known as Behavioral Testing. Black box testing focuses and involves only the inputs and outputs of any code or application without knowing the internal logic.

What are the types of Black box testing?

Functional testing
Non-functional Testing
Regression Testing

A black box test can evaluate relevant subsystems such as the user-interface, application server and database by simulating user activities in the system.

What are the advantages and disadvantages of black-box testing?

Advantages	Disadvantages
No programming skills or knowledge of IT are required to test through this method.	It is difficult to automate.
Internal working and details are not required to conduct black-box testing.	The root cause of the test failure is difficult to identify.
Tests have lower complexity.	Difficult to set test cases without any knowledge of the application functionality.
Various hidden defects are revealed while performing white box testing.	High probability of repeating tests cases.
As we already have the knowledge of the source code, testers can make the testing process more efficient with appropriate test cases.	Complete test coverage is not possible.

Difference between black-box testing and white-box testing

Black-box testing	White-box testing
In this type of testing the internal code is hidden.	Internal working of the application is already known to the tester.
It mainly involves the input and output of the application.	Test cases are set according to the internal logic of the application software.
Tester doesn’t need any advanced IT skills to carry out the test process. Hence mostly done by software testers.	A highly skilled tester is required. It is mostly done by IT professionals.
It tests the functionality of the software.	It tests the proper internal working of the software.
It is not suitable for algorithmic testing because it doesn’t allow access to the internal code.	It can be used for algorithmic testing as well.
It is less time consuming.	It is more time consuming.
Example: entering wrong passwords into the system, searching keywords, etc.	Example: Verifying loops with different inputs

Software testing has traditionally been done at the end of the development process. Nevertheless, it remains the crucial step. We discussed how software can be tested in two useful methods – black box testing and white box testing, but software testing is a much broader term. Stay tuned for more!