White box testing is a software testing approach that handles the inner workings of the system or the structure which is why it is also called structural testing. It deals with tests of internal coding and infrastructure of a software focus on checking predefined inputs against expected and desired outputs.
It is based on the inner workings of an application and revolves around internal structure testing. It is called the white box test or glass test since it denotes the ability for us to see through the box and see the internal workings of the system. some other common names for white box testing are open box testing, transparent box testing, and clear box testing.