Difference Between Black-Box Testing & White-Box Testing

A developer goes through further development and deployment rules for creating applications. Testing is an essential step in the development cycle. 

When it comes to software testing, many techniques need to be used from time to time. Yet the confusion around white, grey, and black testing techniques is most common among all software testing techniques.

They often appear similar, yet the differences between them are very jarring. And this article will shed light on how black box testing and white box testing differ from each other. 

What Is Black Box Penetration Testing?

In the Black box testing, the tester does not know the software or the working systems. It's a kind of testing that focuses more on the behavior than the infrastructure of the software. 

Besides, the testing is more to do with the end-user or works on the outer scale. Black box testing is used on different levels like - integration, unit, system, and acceptability. 

The source of Black box testing depends on the requirements stated by the customer. The process examines the functionality of the software without any coding.

Plus, it does not require any Programming language knowledge know-how. All the tests are designed considering the output and input functions. The process analyzes the test against the needs, identifies the bugs or defects, and sends it back to the development team for rectification. 

It involves a process where the tester gives an input value to check functionality and checks whether functions are giving output. Additionally, the testing method is less time-consuming than White box testing. 

The main objective here is to work depending on the specifications of users. Simply put, it checks application functionality depending on customers' needs. 

How Does Black Box Testing Work?

  • The tester first accesses the system's needs and specifications.
  • To check the SUT handles input - the tester selects legitimate inputs in a positive test scenario. 
  • After which, faulty inputs are generated in the pessimistic test scenario. This step makes sure that SUT can identify the errors.
  • The tester calculates predictive outcomes for each input.
  • With the chosen input, the tester creates test cases.
  • When the tests are carried out - the results are compared to predicted outputs.
  • The flaws are then corrected and rechecked. 

Methods of Black Box Testing:

  • Boundary Value Testing 

It assesses whether the set of values is acceptable for a software system for both valid and invalid input parameters. Besides, it helps cut down the number of test cases, and it's ideal for systems that work on definite ranges. 

  • Decision Table Testing 

In decision table testing, the matrix contains the causes and consequences of the issue. And each column has a different combination. 

  • Equivalence Class Testing 

The testing reduces the number of test cases to a minimum while maintaining the test coverage. 

Different Types of Black Box Testing:

  • Functional Testing - considers systems' functional requirements, and software testers carry out such tests.
  • Non-Functional Testing - considers non-functional criteria and features like - scalability, usability, and performance. 
  • Regression Testing - considers the code changes, upgrades, or system maintenance that ensures new codes don't harm current codes. 

What Is White Box Penetration Testing?

The White box tests the internal infra of the system and denotes the ability to see through the software's outer shell. Developers perform the White box testing, and the results are sent to the testing team for verification. 

Once the process of White box testing is over, testers perform the Black box testing. The main reason for White box testing is to test the application's internal system. 

It is done on the lower levels, including integration and unit testing. Additionally, it requires programming knowledge as it focuses on the code structure, conditions, and different software branches. 

Besides, the main goal of White box testing is to focus on the flow of inputs and outputs. Also, it helps to strengthen the security of the software.

White box testing focuses more on the underlying structure and validates the workflow. Most developers also call White box testing - Clear box testing OR Transparent box testing. 

As the codes are visible to the testers, the process becomes easier and saves time. Also, it is suitable for algorithm testing. 

How Does White Box Testing Work?

  • White box testing tells the developer about the internal flaws of the security. 
  • It checks the paths in a coding process that are poorly organized or broken. 
  • Specific inputs take the paths in the testing through programs.
  • The expected results tell the developer about the software coding.
  • All the conditional loops are useful in different situations.
  • It helps with individual testing of function, statement, and object.
  • It ensures that there is no issue in the operating flow. 
  • It helps determine sets of predetermined inputs to the desired outputs to identify the errors when the inputs fail to provide outcomes.  


Methods of White Box Testing:

  • Statement Coverage 

Statement coverage in White box testing helps you check whether each line in the coding process runs at least once.

  • Branch Coverage 

Branch coverage is performed only once, but this test determines coverage and the control flow graph results. 

  • Path Coverage 

Path coverage examines all the program pathways that make the job easier for the development team. 

Automated test cases can become useless if the codes keep changing. However, code implementation is vital for White box testing, and proper knowledge is required. White box testing is implemented after the detailed design document. 

Differences Between Black Box Testing & White Box Testing

  • In Black box testing, the testing is performed without the knowledge of internal structure or coding, whereas White box testing requires the knowledge of codes and internal structure. The developer performs the White box testing and sends it to the Black box tester. 
  • When you compare Black box and White box testing methods, the former does not require programming knowledge, but the White box requires programming knowledge for testing. 
  • Black box testing focuses more on the software behavior, but White box testing's main function is to test the internal operation of the software or application. 
  • Another key difference is that the Black box focuses more on the end-user, whereas the White box focuses on the path, branches, code structure, and conditions. 
  • Black box testing provides a low granularity report, and White box provides a high granularity report. 
  • Talking about the time taken - Black box testing may not consume time, and testers can perform it quickly. In contrast, White box testing is time-consuming and may require extra time. 

It isn't easy to achieve 100% testing, but you can always raise the percentage with a successful white box and black box testing. Also, automation is not easy in Black box testing as the tester and programmers depend on each other.

On the other hand, it is easier for the development team to automate white box testing. And so, the key lies in understanding both testing techniques in their differences. To make software delivery impeccable, white box and black box testing is an important step that should be done thoroughly. You can hire dedicated developers in India to perform testing successfully besides developing your software and also you can secure your application security with Appknox's security researchers.


Published on Jul 25, 2022
Harikrishna Kundariya
Harikrishna Kundariya is a marketer, developer, IoT, ChatBot & Blockchain savvy, designer, co-founder and director of eSparkBiz Technologies. His 8+ experience enables him to provide digital solutions to new startups based on IoT and ChatBot.


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