Testing Techniques: Black Box Technique

Black box testing, also called functional testing and behavioral testing, focuses on determining whether or not a program does what it is supposed to do based on its functional requirements. Black box testing attempts to find errors in the external behavior of the code in the following categories:

• Incorrect or missing functionality;
• Interface errors;
• Errors in data structures used by interfaces;
• Behavior or performance errors; and
• Initialization and termination errors.

Through this testing, we can determine if the functions appear to work according to specifications. However, it is important to note that no amount of testing can unequivocally demonstrate the absence of errors and defects in your code. It is best if the person who plans and executes black box tests is not the programmer of the code and does not know anything about the structure of the code. The programmers of the code are innately biased and are likely to test that the program does what they programmed it to do. What are needed are tests to make sure that the program does what the customer wants it to do. As a result, most organizations have independent testing groups to perform black box testing. These testers are not the developers and are often referred to as third-party testers. Testers should just be able to understand and specify what the desired output should be for a given input into the program, as shown in Figure.



A black-box test takes into account only the input and output of the software without regard to the internal code of the program