Equivalence class partition method for test case design method

　　 One . Method introduction

　　 Divide equivalence class ： 1) Effective equivalence class 2) Invalid equivalence class

　　 Criteria for dividing equivalence classes ：

　　1) Complete test 、 Avoid redundancy ;

　　2) It is important to partition equivalence classes ： Partition of sets , Divided into a set of disjoint subsets , And the subset is not the whole set ;

　　3) And the whole collection ： completeness ;

　　4) Subsets do not intersect each other ： Ensure a form of non redundancy ;

　　5) Identify... In the same category ( choice ) A test case , In the same equivalence class , Often deal with the same , The same processing is mapped to " Same execution path ".

　　

　　 The method of dividing equivalence classes

　　1) When the input condition specifies the value range or the number of values , Then we can establish a valid equivalence class and two invalid equivalence classes .

　　2) A set of input values is specified in the input condition or " How to " Under the same conditions , A valid equivalence class and an invalid equivalence class can be established ;

　　3) If the input condition is a Boolean quantity , A valid equivalence class and an invalid equivalence class can be determined .

　　4) Set of values specified in the input data ( Assume n individual ), And when the program has to process each input value separately , Establish n Valid equivalence class and invalid equivalence class .

　　 example ： The input condition indicates that the educational background can be : Specialty 、 Undergraduate 、 master 、 Doctor, one of the four , Then take these four values as the four effective equivalence classes , In addition, any degree other than the four is regarded as an invalid equivalent class .

　　5) In the case of rules that must be followed for input data , A valid equivalence class can be established ( Conform to the rules ) And several invalid equivalent classes ( Breaking the rules from different angles );

　　 Design test cases

　　 After establishing the equivalence class , The equivalence class table can be established , List all the equivalence class input conditions ： Effective equivalence class 、 Invalid equivalence class , Then, the test cases are designed according to the following three principles ：

　　1) Specify a unique number for each equivalence class ;

　　2) Design a new test case , Make it cover as many effective equivalence classes as possible , Repeat this step , Until all valid equivalence classes are covered ;

　　3) Design a new test case , Make it cover only one invalid equivalent class that has not been covered , Repeat this step , Until all invalid equivalence classes are covered .

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