Black Box Testing in software

it is , also known as Behavioral Testing, is a software testing method
in which the internal structure/ design/ implementation of the item being tested is not
known to the tester. These tests can be functional or non-functional, though usually
functional.

                      This method is named so because the software program, in the eyes of the tester, is

like a black box; inside which one cannot see. This method attempts to find errors in
the following categories
Incorrect or missing functions
Interface errors
Errors in data structures or external database access
Behavior or performance errors
Initialization and termination errors