ISBN : 978-81-963532-2-3 (E-Book) as users’ manual, software requirements specification document, design document, test documents, etc. A systematic software development style ensures that all these documents are produced in an orderly fashion. TESTING Program Testing Testing a program consists of providing the program with a set of test inputs (or test cases) and observing if the program behaves as expected. If the program fails to behave as expected, then the conditions under which failure occurs are noted for later debugging and correction. Some commonly used terms associated with testing are: Failure: This is a manifestation of an error (or defect or bug). But, the mere presence of an error may not necessarily lead to a failure. Test case: This is the triplet [I,S,O], where I is the data input to the system, S is the state of the system at which the data is input, and O is the expected output of the system. Test suite: This is the set of all test cases with which a given software product is to be tested. Aim of Testing The aim of the testing process is to identify all defects existing in a software product. However for most practical systems, even after satisfactorily carrying out the testing phase, it is not possible to guarantee that the software is error free. This is because of the fact that the input data domain of most software products is very large. It is not practical to test the software exhaustively with respect to each value that the input data may assume. Even with this practical limitation of the testing process, the importance of testing should not be underestimated. It must be remembered that testing does expose many defects existing in a software product. Thus testing provides a practical way of reducing defects in 88 Software Engineering Keerthana P, Manasa KN, Ganga D Bengal
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