Grey Box Testing

What is Grey Box Testing?

As one can understand with the name Grey box testing, it is a combination of White Box testing (tester having the knowledge of internal functionality/ code of the application) and Black Box testing (tester having no knowledge of internal functionality). It is performed on the software product with the partial/ limited information of the internal functionality. Testers usually have access to the database, detailed design documents and information about the requirements of the product. Testers have the knowledge of the basic working of code and the algorithms used which is helpful in designing the test cases but does not know the exact code so the testing is done normally from the tester’s viewpoint.

Why do we Need Grey Box Testing?

In today’s software application, it is very important for a tester to have a basic understanding of the source code so that testing can be done in-depth and the scope of testing can be widened. Some of the important reasons demonstrating the need of Grey box testing for testers are given below:

• One of the most important reasons for the Grey box testing is that it reduces the dependence of tester on the developer for every small issue found in an application. As the tester having the basic knowledge about the application code can find out the reason and fix it by itself if required.
• It combines the advantages of both the Black box testing and White box testing.
• It helps in increasing the scope of testing by understanding the application better from both developer and tester point of view and hence improves the quality of software.
• It gives developers enough free time to fix the bugs/ issues raised by the testing team.

How does it works?

Basic steps are performed for performing the Grey box testing of an application:

Step 1: White box testing to understand the code and flow of the whole program of software application.

Step 2: Designing the detailed test cases with the knowledge of the above code to have the maximum code coverage.

Step 3: Black box testing in order to test the above test cases with the tester’s point of view rather than the developers’ viewpoint of an application.

Top 4 Grey Box Testing Techniques

There are basically 4 techniques used for testing any software application:

1. Pattern Testing

In the Pattern testing, analysis of the previous records of the defects is performed and the problem in the code is looked into due to which the defect arising. Pattern testing is performed for the software application which has been developed previously on the same pattern as there is a possibility of arising the same defect again so previously encountered issues can be tested properly in the next software in order to avoid risks.

2. OAT or Orthogonal Array Testing

OAT testing is performed for the complex application in order to cover the maximum code and GUI functions with a minimum number of test cases by performing the permutations and combinations of the test data represented in an array with the variables representing the columns and the test cases in the rows.

3. Regression Testing

Regression testing is performed in order to test whether any change or newly added functionality has not affected the related or previously working software. In Regression testing, testing is mainly focussed around the areas that could be affected due to change, retesting of the fixed bugs, regression around the risky areas that could hamper the application by choosing the baseline tests.

4. Matrix Testing

In this type of testing, all the variables used in the program are defined so that the business and technical risks associated with the variables defined by the developer are tested. Variables play an important role in the overall flow in any software application and testing around it makes it easier and smoother when all the information regarding variables is summarized in one table.

Advantages and Disadvantages

Below are the advantages and disadvantages:

Advantages

Some of the advantages are given below:

• It is unbiased and helps in finding out more scenarios that need to be tested from the developer’s thought and tester’s thought.
• The grey box also helps in verifying the requirements again in the testing phase as all the software requirement documents, architectural diagrams are shared with the testers.
• It reduces the task of testing the software application separately from the functional and nonfunctional perspective as both can be covered in Grey box testing.
• Even though the testers have the knowledge of code, but the Grey box testing is done from the user’s point of view rather than the developer’s point of view.
• It is very much beneficial in Integration testing and Penetration testing of an application.
• In case of small issues in an application (like hyperlink not working on a website, image not loading, etc) unnecessary time is not wasted in filing a bug and submitting to a developer to fix. As the tester have a basic understanding of code can access it and fix it without the interruption of the developer.

Disadvantages

Some of the disadvantages are given below:

• Test coverage is comparatively less in Grey box testing as a comparison to separate Black box testing and white box testing.
• Practically, it can not be performed completely as not all organizations allow access to code to the testers due to security reasons.
• For large applications, it takes a lot of time in covering each input path which in turn increases the project budget and can hamper the project deadline.
• It is very challenging for a tester to understand each requirement and algorithm used to design the test cases accordingly.
• Failure in some interrelated functionality of the application can cause hindrance while performing it and the association of bugs in Grey box testing is difficult in the case of a distributed environment.

Conclusion

The above description clearly explains what is it and why is it important in the field of software testing? It is quite beneficial and is trending in the modern IT world as it combines the advantages of both the black box and white box testing. It is helpful especially in extensive testing of web-based applications and Functional testing of the application.

Recommended Articles

This is a guide to Grey Box Testing. Here we discuss the basic concept and top 4 grey box testing techniques along with advantages and disadvantages. You can also go through our other suggested articles to learn more –

1. Levels of Software Testing
2. Types of Security Testing
3. White Box Testing vs Black Box Testing
4. Domain Testing