Describe white box and black box testing of software.

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 Solution:-

White Box Testing (also known as Clear Box Testing, Open Box Testing, Glass Box Testing, Transparent Box Testing, Code-Based Testing or Structural Testing) is a software testing method in which the internal structure/ design/ implementation of the item being tested is known to the tester. The tester chooses inputs to exercise paths through the code and determines the appropriate outputs. Programming know-how and the implementation knowledge is essential. White box testing is testing beyond the user interface and into the nitty-gritty of a system. This method is named so because the software program, in the eyes of the tester, is like a white/ transparent box; inside which one clearly sees.

EXAMPLE: A tester, usually a developer as well, studies the implementation code of a certain field on a webpage, determines all legal (valid and invalid) AND illegal inputs and verifies the outputs against the expected outcomes, which is also determined by studying the implementation code. White Box Testing is like the work of a mechanic who examines the engine to see why the car is not moving.

Black -box testing: Black Box testing: In this method the analyst examines the specifications to see what the program must do under various conditions. Test cases are then developed for a condition or a combination of conditions and submitted for processing. By examining the results the analyst can determine if the specified requirements are satisfied. Black-box testing attempts to find errors in the following categories:

  • Incorrect or missing functions
  • Interface errors
  • Errors in data structures or external database access
  • Behaviour or performance errors
  • Initialization and termination errors

EXAMPLE:

A tester, without knowledge of the internal structures of a website, tests the web pages by using a browser; providing inputs (clicks, keystrokes) and verifying the outputs against the expected outcome.

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