Difference Between White-Box and Black-Box Testing

White-Box vs Black-Box Testing
 

The terms White-Box and Black-Box are used in software engineering. Those are two of the testing approaches that are used in software testing, the process of giving assurance about the quality of the software to the customer. Software testing (which is usually performed by executing the software) is conducted with the intention of finding mistakes (also known as software bugs) in the software.

What is White-Box Testing?

White-box testing is used to test a software system based on the structure of the system. It is more like a transparent box through which we can see what is going on inside. It tests deeply on how each module of the system responses according to the given inputs. Such testing takes much time as it is necessary to check control structures, loops, conditions, functions, etc. Testing techniques of this approach includes data flow testing, control flow testing, branch and path testing for each unit. To perform this kind of testing highly technical testers are needed. By performing a white-box test, it is easier to track down the bugs that are available in the system. White-box testing adds an extra load to a project, because, in some situations, it is necessary to generate test cases as separate projects for individual test areas. Therefore, this finally has negative effects to the cost of the project and schedule.

What is Black-Box Testing?

Black-box testing is used to test only the functionality of the system regardless of how the system is performing an action. It is mainly targeted to make sure that the system requirements are satisfied. It is similar to a closed box where we only know what we are feeding and finally it gives an output, but do not know how that output was produced. The testing techniques include; decision table testing, state transition tables, equivalent partitioning, etc. for a higher level testing. This testing takes lesser time compared to white-box testing as this only considers about testing whether the system gives expected output according to the given input. Test cases are generated only according to the system requirement. Technical skills of the tester are not highly expected. If an error in the system occurs, it is not easy to track it as it does not test the internal process.

Typically, both of these techniques are used in software development environment, to make sure that the whole software is working properly. There is no specific order to perform those two testing, and the approaches do not belong to any specific phase of software development life cycle. However, black-box testing may be performed by a separate team while white-box testing preferably is performed by the developers or programmers themselves, in addition to a separate testing team.