Out of the multiple software testing techniques, methods, and processes, two of the most prominent ones are White Box Testing and Black Box Testing.
What is White Box Testing
This testing methodology enables a tester (software developers, in general) to look into the internal structure and sub-system of an application while testing. It provides a degree of sophistication and freedom to a tester, allowing him/her to interact with an application’s objects and not only just the interface. Some of the techniques of white box testing include statement coverage, decision coverage, condition coverage, decision/condition coverage, and multiple condition coverage.
What is Black Box Testing
In this method, a tester tests the software without having access to the internal structure or code of an application/program/software. He/she only looks at the available inputs and the expected output from each input. Some of the techniques of black box testing are: boundary value analysis, equivalence class partitioning, decision table based testing, cause-effect graphing technique and error guessing.
A tabular representation of the differences between white box testing and black box testing is displayed below:
|Basis of Differentiation||White Box Testing||Black Box Testing|
|Performed at Levels||White Box Testing is applicable to lower levels like Unit and Integration levels.||This method of testing is mainly applicable to higher levels of testing like Acceptance and System|
|Performed by||Software Developers||Independent|
|Programming Knowledge||Professionals performing this method to test the functionality of an application should be knowledgeable in multiple programming languages.||No such criteria is necessary when it comes to black box testing|
|Basis of Test Case Design||Detailed design documents are essential to design test cases when testing an application using the white box testing method||Requirement specifications documents are enough to design test cases for black box testing|
|Knowledge of Implementation||Required||Not required|
|Technical Knowledge||Tester must have thorough technical knowledge||A professional with minimum technical knowledge could also implement this type of testing method|
|Level of Complexity||Extreme||Moderate|
|Focus of Testing||White box testing focuses on how the inputs are carried out and the code of a system||This type of testing focuses on what is being carried out and the functionality of a system|
|Other Meaning||Structural or Interior test||Functional or External test|
|Other Names||Structural, Glass-box, Clear-box, Open-box, Transparent-box testing||Functional, Behavioral, Opaque-box, Closed-box testing|
In conclusion, both white box testing and black box testing have their own unique features, advantages and disadvantages. Both methods address particular non-redundant needs, and in that respect, they should be employed in a complementary manner to be assured of the comprehensiveness of the software testing process.