White box testing, also known as clear box testing, structural testing, or code-based testing, is a software testing approach that involves examining the internal workings of a software application's code to verify if it functions correctly and meets the requirements.

The goal of white box testing is to identify defects in the code's internal structures, including branches, loops, and conditional statements. Testers use their knowledge of programming languages, code structures, and software architecture to create test cases that exercise different code paths and validate the expected behavior.

Some of the most commonly used white box testing techniques are:

1.    Statement Coverage: This technique involves testing each statement in the code to ensure that it is executed at least once during testing.

2.    Branch Coverage: This technique involves testing all possible branches of code, including loops, if-else statements, and switch cases.

3.    Path Coverage: This technique involves testing all possible paths through the code, including loops and recursive functions.

4.    Condition Coverage: This technique involves testing all possible combinations of boolean conditions in the code.

5.    Decision Coverage: This technique involves testing all possible decisions made in the code, including if-else statements and switch cases.

6.    Loop Coverage: This technique involves testing all possible paths through loops, including zero iterations, one iteration, and multiple iterations.

In summary, white box testing is a critical component of software testing that helps ensure that software is functional, reliable, and meets user requirements. The various white box testing techniques help testers uncover defects and ensure that the code is robust and efficient.