From: Chinese computer users - SEOUL Author: China Software Testing Center Testing Center [2003/09/08]
Software test has many ways, in which black box test is one of the two types of test methods widely used. "Black Box" is measured by a functional black box test, also known as functional test or data-driven test. It is used to detect if each function can be used normally under conditions of the function of known products. When testing, the program is considered a black box that cannot be opened. When the internal structure and internal characteristics are not considered, the tester tests in the program interface, which only checks whether the program function is normal according to the requirements of the requirements specification. Using, whether the program can properly receive input data to generate the correct output information, and maintain external information (such as database or file) integrity. "Black Box" method is the external structure of the program, regardless of the internal logic structure, testing the software interface and software function. The "black box" method is exhausted input test, only use all possible inputs as a test case, in order to find all the errors in the program in this way. In fact, there is a number of infinity tests, but also do not only test all legal inputs, but also test those non-legal but possible inputs. The two basic methods of "black box" have two basic methods, which are tested through testing and failure. When performing the test, it is actually confirming what the software can do, but will not try their ability. Software testers use only the easiest and most intuitive test cases. When designing and executing a test case, you always have to pass the test. Take a look at whether the software basic function can be implemented before making a destructive test. This is very important, otherwise it will be strange when using software normally. Why is there so many software defects? After confident that the software is running correctly, you can take a variety of means to find defects by engaging in "" software. Test cases designed and implemented purely to destroy software, known as failures or forced events. The design method of the black box test is tested by the user's point of view, and it is tested from the corresponding relationship between input data and output data, which does not involve the internal structure of the program. Obviously, if the external feature itself has a problem or specifications, it is not possible to use a black box test method. The black box test focuses on the functional requirements of the test software, mainly trying to find several types of errors: the function is wrong or omission, interface errors, data structures, or external database access errors, performance errors, initialization, and terminating errors. Specific black box test methods include equivalent class division, causal map, orthogonal experimental design, boundary value analysis, determination table driven, function test, etc. In use, it is natural to appropriately select the method for the development project. ◆ Equivalent class division equivalence class is a typical black box test method. It is designed to design test cases that can not consider the internal structure of the program, which is based on the requirements and description of the program, ie demand specifications. Carefully analyze and scrutinize the needs of the instructions, especially functional requirements, distinguish between the requirements and outputs of the inputs in the description and decompose. Since the number of exhaustive tests is too large, it is not actually completed, so that we will select a part of the possible data as a test case. For example, without understanding the equivalent allocation technology, after testing 1 1, 1 2, 1 3 and 1 4, is it necessary to test 1 5 and 1 6? Can I confidence? Is them correct? So 1 999 ... (can you enter the maximum value)? Is this test case different from other use cases? Do you belong to another category? Another equivalent interval? This is a problem that software testers must take into account. The equivalent category or equivalent interval refers to a set of test cases that test the same goal or expose the same software defect. What is the difference between 1 999 ... and 1 13? As for 1 13, it is like an ordinary addition, which is no different from 1 5 or 1 392, while 1 999 ... is an extreme condition of the neighborhood.
