1. Division of Equivalence classes:
The equivalence class partitioning method is a typical and important black box test method, which divides all possible input data (valid and invalid) into several equivalence classes. Then select the representative data from each section as a reasonable classification of test cases, the test cases are composed of valid equivalence class and invalid equivalence class, so as to ensure the completeness and representativeness of the test case.
1.1 Valid equivalence classes:
A valid equivalence class is a set of reasonable and meaningful input data components for a program specification. The effective equivalence class can be used to verify whether the program implements the pre-defined functionality and performance of the specification. A valid equivalence class can be one or more, dividing several parts according to the input domain of the system, then selecting a few representative data from each part as the test case of data test, and the equivalence class is a collection of input fields.
1.2 Invalid equivalence class:
The invalid equivalence class and the valid equivalence class are opposite, the invalid equivalence class is the non-meaningful and unreasonable input data set for the software specification. Using the invalid equivalence class, you can find out the program exception description, check the function and performance of the program is not in line with the requirements of the specification.
The teacher tells us: When overriding a valid equivalence class, as far as possible, more valid equivalence classes are placed in a test case; When overriding an invalid equivalence class, only one invalid equivalence class is added at a time, so that the cause of the error can be correctly located at the first error.
General equivalence class Partitioning principle:
If there is a clear description of the input in the specification, it is classified according to the specification sheet.
If the input of a value, it is divided by interval
If non-numeric input, then according to the characteristics of attention to classify example of the teacher's class: 50~100 the Science and Technology book
There are two inputs, namely the number of books and the type of books, the number of books according to the interval divided into [0,50], [50,100], (100, +∞), the types of books can be divided into scientific and technical books and non-scientific books.
Then, the valid equivalence class is: 1. Science and Technology book, 2. [50,100]
The invalid equivalence class is: 3. Non-sci-tech books, 4. [0,50], 5. (100, +∞)
Test Case:
75 the legal input of the Science and Technology book cover 1, 2 equivalence class
25 illegal importation of scientific and technical books cover 4, 1 equivalence class
75 non-technical books illegal input covering 2, 3 equivalence class
125 illegal importation of scientific and technical books cover 5, 1 equivalence class
Software Testing second week knowledge summary