What are the causes behind to perform white box testing?

There are three main reasons behind performing the white box testing.

1. Programmers may have some incorrect assumptions while designing or implementing some functions. As a result there is possibility of having logical errors in the program. To identify and correct such logical errors procedural details need to be checked.

2. Certain assumptions on flow of control and data may lead programmer to make design errors. To uncover the errors on logical path, white box testing is required.

3. There may be certain typographical errors that remain unnoticed even after syntax and type checking techniques. These errors can be found during white box testing.