In black-box testing, the tester views the software as a black box, ignoring all the internal structure and behavior. Their only concern is the input provided to the system and the generated output. Black-box testing verifies the program’s behavior against the specified requirements.
During black-box testing, the test conditions are created based upon the software’s functionality but are unaware of how the software works internally. The software is tested from the end user’s perspective and gives a broader picture of the whole system.
Given that the users are only concerned with whether the software works according to their needs and don’t care how it works, black-box testing helps test software usability and anticipate how the customer will use the product.
White-box testing is an alternative strategy to black-box testing, in which a tester views the system as a transparent box. They are allowed to observe the internal implementation of the system, which guides the test. Typically, the software developers perform the white-box testing during the development phase.
In white-box testing, we assume that the tester has some programming knowledge. They try to test each possible branch a program could take in a running system. Knowing what’s inside the box, i.e., taking a look at the source code and the implementation details, it’s possible to test the system more thoroughly.