Equivalent Class Division of Black Box testing
Equivalent class division:
Divide all possible input data, that is, the input field of the program, into several parts (subsets), and then select a small number of representative data from each subset as test cases.
Criteria for dividing equivalence classes:
1. The union of all subsets is the whole set
2. Subsets do not intersect each other
3. Different test cases in the same subset are treated the same, that is, there is "the same execution path".
Two different equivalence classes:
(1) effective equivalence class: a set of reasonable and meaningful input data for the specification of the program.
(2) invalid equivalence class: a collection of unreasonable and meaningless input data for the specification of the program.
