Software components: program, documents, data
Software is written and tested by people, so there is no perfect software, all software has flaws.
Software defects: There is a wide variety of computer systems or programs disrupt the normal running capacity problems, errors or defects dysfunction, mainly in the form of results of error, loss of function, function failure, inconsistent with user needs.
IEEE to define software defects: software defects is the product of the existence of a problem, the final performance is not fully implemented as functions users need not meet or can not meet all user needs.
From the inside of the product point of view: is a software product development software defects or problems errors, errors present during maintenance.
From the product point of view the outside: System software defect is required to achieve a certain function failure or breach.
Software development life cycle: the software requirements analysis, software design and software coding and other sectors.
5 types of software defects:
(1) the software does not implement the functions required product specifications
(2) An error has occurred Software product description should not appear
(3) the software product features not mentioned in the specification
(4) Unrealized software product specifications, although not explicitly mentioned features but that should be implemented
(5) software difficult to understand, easy to use, run slowly ---- testers look from the perspective of the end user will think bad ----
A variety of software defects, the cause is not the same that with computer software it may be a problem, with the problem need to be tested, identify problems, solve problems, and therefore only the software testing.
After accumulated a large number of test research and test development, main causes of software defects can be summarized as follows:
(1) needs to explain errors
(2) user-defined error
(3) demand records error
(4) design specification error
(5) Description coding error
(6) program code error
(7) Other error, data input, etc.
The cost of repairing software defects
Software development experience requirements analysis, design, programming, testing, to process publicly available in the entire process, software bugs are likely to experience a variety of issues.
Over time, the cost of repairing software defects multiplied.
Find related loss of function in the analysis, it can immediately fill. The cost is almost negligible. And found in the release missing or defective function, then the time to add a function of the cost is quite large, so you want to test as soon as possible.
References: based tutorial software testing, software testing division Tutorial