White box testing - Definition and Overview

White box testing, clear box or structural testing is used in computer programming, software engineering and software testing to check that the outputs of a program, given certain inputs, conform to the internal design and implementation of the program.

The term white box indicates that the tester closely examines the internal implementation of the program being tested. A complementary technique, black box testing or functional testing, checks that the program performs to its specification without examining its internal implementation.