Gray Box Testing: The Balanced Approach to Software Quality

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gray box testing

What is Gray Box Testing?

The color Gray takes birth when black and white comes into a colorful union. Much like in the world of hues, the technical space combines the two testing categories of black box and white box to give birth to Gray Box Testing. Gray Box testing is used in application or software testing. Unlike white box or black box testing, there is only partial knowledge about the internal coding. It can be said that Gray Box testing is a combination of Black Box testing and White Box Testing.

Gray Box Testing

In black box testing the internal structure is not visible, in White Box Testing the internal structure is visible, and in gray box testing the internal structure of the code is partially visible. With the help of gray box testing, we can identify the abnormalities in the code and also understand if the application is not used correctly. Any error of the web can be easily found by this type of testing. 

Gray Box Testing Techniques

With the help of Gray Box testing, it is possible to do penetration testing. If there is a scenario where an employee wants to manipulate any application then these techniques can help make them visible. Also if there is a situation where there is an outsider who wants to exploit the vulnerable parts then the techniques can be helpful. 

Gray Box testing helps the application to work in the expected style by the users. It ensures that unauthenticated users do not get access to data or any functionality. Some techniques that can be incorporated for gray box testing, are:

Matrix Testing 

With the help of matrix testing, every variable in the application is examined. The developer categorizes the risks related to business and technique. The application variables are listed and then every variable is tested with respect to the risk it might have. This technique also helps in understanding the variables which are not used or are not optimized. 

Regression Testing

 By applying regression testing we can check if errors have been caused while trying to fix bugs or do application changes. This technique helps in confirming that the changes that are being made to an application only make it better and not changes its structure. While regression testing takes place the inputs and outputs might have to be changed depending on the scenario. 

Pattern Testing 

As the name suggests pattern testing helps in finding patterns. This technique identifies the defects which have occurred earlier on and finds the pattern to predict defects that may appear in the future. The defect found out can be used to understand whether the fixes used were efficient enough. This information can be utilized for future application building and testing.  

Orthogonal Array Testing 

If an application consists of a small number of inputs and complex testing techniques are not required then orthogonal array testing can be implemented. This helps in optimizing the test cases. Therefore a balance is maintained in the system. It is a systematic process and can be used for testing paired interactions.  

Steps for Gray Box Testing  

The steps of Gray Box Testing are:

  • Firstly the inputs are identified.
  • After identifying inputs, the outputs are identified. 
  • Thereafter identify the major paths. 
  • After the major paths are identified, figure out the subfunctions.
  • Once all the subfunctions are figured out, develop inputs for them. 
  • After developing inputs, develop the outputs.  
  • When the inputs and outputs are developed, execute the test cases.
  • Verify the results.
  • Repeat the steps for accuracy. 
steps for gray box testing

Automated Testing Tools for Gray Box Testing 

The automated testing tools are designed to test applications for special purposes. For example, selenium is to check web applications on browsers only,  appium is used for mobile application testing automation. So the different automation testing tools are:

Advantages and Disadvantages of Gray Box Testing 


  • Gray box testing gives the advantages of black-box testing and white-box testing. 
  • The product quality is better because the inputs of developers and testers are considered.
  •  The testing process is comparatively shorter.
  • It allows the developer to fix defects.
  • The testing goals are clear which makes it an easier process for developers as well as testers.
  • Testers are not required to be experts. 
  • Gray box testing is cheaper than integration testing.
  • Testing is done on the basis of high-level database diagrams and data flow diagrams.  


  • Gray box testing cannot be used for the testing of algorithms.
  • It might be difficult to design the test cases.
  • Even though it is a combination of black box and white box testing, it does not have the full benefits of white box testing. 
  • There might be difficulty in understanding the link between a defect and its root cause.

Difference Between Black Box, White Box, and Gray Box Testing

Black Box vs White Box vs Gray Box Testing

Black Box Testing White Box TestingGrey Box Testing
The internal structure of the code is known. The internal structure of the code is partly known.Also known as closed-box testing, data-driven testing, and functional testing.
Also known as clear box testing, structural testing, and closed testing. Algorithm testing cannot be done.Also known as translucent testing. 
Most time-consuming process.Algorithm testing can be done and is recommended.Algorithm testing cannot be done. 
Hidden errors are difficult to detect.Hidden errors are easily detected. Difficult to discover hidden errors. 
The testing is done by the tester, developer and user.The testing is done by the tester and developer. The testing is done by the tester, developer and user.
The testing is done by the tester, developer, and user.Least time-consuming process.Takes less time than black box. 
The least exhaustive type of testing.Most exhaustive form of testing.It is partially exhaustive.
It has the largest testing space of inputs. It has the smallest testing space of inputs. The testing space is larger than white box testing but smaller than white box testing. 


What is Gray Box Testing?

If there is partial availability of knowledge about the internal structure of the software development it is known as Gray box testing. It is a combination of white box testing and black box testing. 

What is Gray Box Vulnerability Testing?

If there is a breacher who has already breached the perimeter and has access to the internal structure, Gray Box Testing can be used to find it out. It can be made more efficient by giving a background to the security consultant. This is known as Gray Box Penetration Testing. 

Who conducts Gray Box Testing?

The tester who conducts Gray Box Testing needs to partly understand the internal structure and codes. This is because the input has to be fed through the front end whereas it has to be verified at the back end.  

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Bluein Christian

Content Writer with experience of 6+ years. Have experience writing content for different industries, such as travel, education, fashion, and more. A creative person by birth and by profession. She loves learning new concepts and creating useful content about them. She loves traveling and is always up for new challenges.


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