Whitebox testing

“White box testing” (also known as clear, glass box or structural testing) is a testing technique which evaluates the code and internal structure of the program.

In white-box testing the tester is concentrating on how the software does it. For example, a structural technique may be concerned with exercising loops in the software.

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.

Definition by ISTQB

• white-box testing: Testing based on an analysis of the internal structure of the component or
  system.

White Box Testing Techniques:

• Statement Coverage –This technique is aimed at exercising all programming statements with minimal tests.
• Branch Coverage – This technique is running a series of tests to ensure that all branches are tested at least once.
• Path Coverage – This technique corresponds to testing all possible paths which means that each statement and branch is covered.

WHITE BOX TESTING ADVANTAGES

• Testing can be commenced at an earlier stage. One need not wait for the GUI to be available.
• Testing is more thorough, with the possibility of covering most paths.

WHITE BOX TESTING DISADVANTAGES

• Since tests can be very complex, highly skilled resources are required, with thorough knowledge of programming and implementation.
• Test script maintenance can be a burden if the implementation changes too frequently.
• Since this method of testing it closely tied with the application being testing, tools to cater to every kind of implementation/platform may not be readily available.