Black-box testing is a method of software testing that tests the functionality of an application as opposed to its internal structures or workings (see white-box testing). Specific knowledge of the application's code/internal structure and programming knowledge in general is not required.

When some one say black box means we don't have access to see the object kept in that box.In the same way tester does test only the functionality of application and he never take tension to go through internal structure and code. This kind of testing is also known as functional testing..

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Also known as functional testing. Asoftware testing technique whereby the internal workings of the item being tested are not known by the tester. For example, in a black box test on a software design the tester only knows the inputs and what the expected outcomes should be and not how the program arrives at those outputs. The tester does not ever examine the programming code and does not need any further knowledge of the program other than its specifications.