White box testing strategy deals with the internal logic and structure of the code. White box testing also known as glass, structural, open box or clear box testing, tests code written, branches, paths, statements and internal logic of the code etc.
In order to implement white box testing, the tester has to deal with the code and hence is needed to possess knowledge of coding and logic i.e. internal working of the code. White box test also needs the tester to look into the code and find out which unit/statement/chunk of the code is malfunctioning. White box testing is applicable at unit, integration and system level however it is mainly done at unit level.
Black box testing Black-box test design treats the system as a "black-box", so it doesn't explicitly use knowledge of the internal structure. It takes an external perspective of the test object to derive test cases. These tests can be functional or non-functional, though usually functional. The test designer selects valid and invalid input and determines the correct output. There is no knowledge of the test object's internal structure.
This method of test design is applicable to all levels of software testing: unit, integration, functional testing, system and acceptance.
