BLACK BOX TESTING, 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.
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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
Errors in data structures or external database access
Behavior or performance errors
Initialization and termination errors
Definition by ISTQB
black box testing: Testing, either functional or non-functional, without reference to the internal structure of the component or system.
black box test design technique: Procedure to derive and/or select test cases based on an analysis of the specification, either functional or non-functional, of a component or system without reference to its internal structure.