What to learn in Software testing (1) Black Box testing tutorial

Black box testing is also called functional testing, which is to test whether each function can be used normally. In testing, the program is regarded as a black box that cannot be opened. In the case of completely ignoring the internal structure and internal characteristics of the program, the program interface is tested. It only checks whether the program functions normally according to the requirements specification, and whether the program can properly receive input data and produce correct output information. Black-box testing focuses on the external structure of the program, regardless of the internal logic structure, mainly for software interface and software function testing.

Black-box testing is performed from the perspective of the user, starting from the correspondence between input data and output data. Obviously, if there is a problem with the design of the external feature itself or if the specification is wrong, the black box test method will not find it.

role

Black-box testing focuses on testing the functional requirements of the software and tries to find the following types of errors.

Incorrect or missing functionality;

interface error;

Input and output errors;

Database access error;

performance error;

initialization and termination errors, etc.

Overview of test methods

Theoretically, black box testing can only detect all errors in a program by using exhaustive input testing, considering all possible inputs as test cases. In fact, there are an infinite number of test cases, and one has to test not only all legitimate inputs, but also those that are illegal but possible. In this case, complete testing is impossible, so we need to conduct targeted testing, guide the implementation of testing by developing test cases, and ensure that software testing is organized, step-by-step, and planned. Black-box testing behavior must be quantified to ensure software quality, and test cases are one of the ways to quantify testing behavior. Specific methods of black box test case design include equivalence class partition method, boundary value analysis method, error inference method, causality diagram method, decision table driving method, orthogonal test design method, function diagram method, scenario method, etc.

Equivalence classes are divided into several parts (subsets), and then select a few representative data from each part as test cases. The representative data of each class plays an equivalent role in the test to the other values in that class. This method is an important and commonly used black box test case design method.