Which characteristic defines white box testing?

White box testing is defined by its focus on the internal structure, design, and implementation of the software. This approach allows testers to have full visibility of the application's code and internal workings, which enables them to create test cases that directly examine paths, conditions, and logic within the program.

By analyzing the structure of the component or system, testers can identify hidden errors that may not be evident through external testing alone. This detailed examination helps in ensuring that all pathways through the code are tested, contributing to higher coverage of the application’s functionality.

While other approaches to testing may focus on specifications or documentation, white box testing specifically requires knowledge of the internal architecture of the software. This characteristic is what distinguishes white box testing from other testing methodologies, such as black box testing, which does not consider the internal logic of the code when designing test cases.