SOFTWARE TESTING TECHNIQUES

Software testing is a critical element of software quality assurance and represents the ultimate review of specification, design, and code generation It is not unusual for a software development organization to
expend between 30 and 40 percent of total project effort on testing. In the
extreme, testing of human-rated software (e.g., flight control, nuclear reactor monitoring) can cost three to five times as much as all other software engineering steps combined!

What is it? Once source code has been generated, software must be tested to uncover (and correct) as many errors as possible before delivery to your customer. Your goal is to design a series of test cases that have a high likelihood of finding errors— but how? That’s where software testing techniques enter the picture. These techniques provide systematic guidance for designing tests that

(1) Exercise the internal logic of software components, and
(2) Exercise the input and output domains of the program to uncover errors in program function, behavior. and performance.

Who does it? During early stages of testing, a software engineer performs all tests. However, as the testing process progresses, testing specialists may become involved.

What are the steps? Software is tested from two different perspectives: (1) internal program logic is exercised using “white box” test case design techniques.
(2)Software requirements are exercised using “black box” test case design techniques.
In both cases, the intent is to find the maximum number of errors with the minimum amount of effort and time.

What is the work product? A set of test cases designed to exercise both internal logic and external requirements is designed and documented, expected results are defined, and actual results are recorded.
Our objective is to design tests that systematically uncover different classes of errors and to do so with a minimum amount of time and effort.