Software Testing Methods - White Box Testing
In contrast to black-box testing, White-box testing means the QA engineers will have complete access to the internal data structures of the software and internal representation and implementation of the software. In this method, QA engineer will have enough knowledge about the software and very well aware of possible workflows in the software.
One example is API testing - This testing is very much useful, where you software acts as a library and intermediate component. API stands for Application Programming Interfact. Currently all apps are coming up with APIs. Most popular ones are Facebook API, EBay, Android. etc. To test those APIs given to the developers across the world, the tester should have the knowledge of function arguments and return values. This is an example for white box testing.
Also the tester can execute the test cases, where all parts of the codes in a function / module are executed or not. There are profiling tools available for this where they can monitor what are all the lines are executed, how many times, how much time it took to execute, etc.