What is Gray Box Testing or Grey Box Testing?

It is the combination of Black Box testing and White Box testing. In Black Box testing tester is not aware of internal codes while in White Box testing internal codes of structures are known to the tester. In the Gray Box testing the tester has knowledge of some parts of internal structure.

This involves having access to internal data structures and algorithms for the purpose of designing the test cases. Based on this limited knowledge, the test cases are designed and the tester tests the application from outside on Black Box level. The Gray Box tester treats the program as a Black Box that must be analyzed from outside.

Gray Box testing is considered to be non-intrusive and unbiased because it does not require that the tester to have access to the internal code. The tester may know how the system components interact but does not have detailed knowledge about internal program functions and operations. A clear distinction exists between the developer and the tester, thereby minimizing the risk of personnel conflicts.

Gray-Box testing is beneficial because it uses the technique of Black-Box testing and combines it with the code-targeted systems in White-Box testing. It is called Gray Box testing because the application for tester is like a transparent box and tester can see inside it but not fully transparent & can see partially in it.

Advantages of Gray Box Testing

• Offers combined benefits: As Gray-Box testing is a combination of white-box and black-box testing, it serves advantages from both the testing.
• Non-Intrusive: It is based on functional specification, architectural view whereas not on source code or binaries which makes it invasive too.
• Unbiased Testing: Gray-Box testing maintains a boundary line for testing between tester and developer avoiding conflicts.

Negative Effects

• Partial code coverage: In Gray-Box testing, source code or binaries are missing because of limited access to the internal or structure of the applications which results in limited access for code path traversal.