Several common design methods of test cases [easy to understand]

Hello everyone , I'm wang Jun , An architect who can write code and recite poetry . Today, let's talk about several common design methods of test cases [ Easy to understand ], I hope it can help you make progress !!!

The common design methods of test cases are ： Division of equivalence class 、 Boundary value analysis 、 Wrong guess 、 Decision table method 、 Orthogonal experiment .

One 、 Division of equivalence class

seeing the name of a thing one thinks of its function , seeing the name of a thing one thinks of its function , Equivalence class division , Is to divide the test scope into several disjoint subsets , Their union is complete , Select several from each subset Representative As a test case . 　　 for example , We want to test whether a user name is legal , The user name is defined as ：8 A character consisting of digits . 　　 We can draw the molecular set first ： Empty user name ,1-7 Digit number ,8 Digit number ,9 Digits or more , The digital . 　　 Then select from each subset A number of Representative values ： 　　 Empty user name ：“” （ Invalid equivalence class instance , For software specifications , It doesn't make sense 、 Unreasonable input ） 　　1-7 Digit number ：”234” （ Invalid equivalence class instance ） 　　8 Digit number ：”00000000” （ Valid equivalence class instances , Be able to check whether the program realizes the functions and performance specified in the specification ） 　　9 Digits or more ：”1234567890” （ Invalid equivalence class instance ） 　　 The digital ：”abc&!!!” （ Invalid equivalence class instance ） 　　 they 5 individual , Is to divide the selected test cases with equivalence classes . actually , about 1-7 For a subset of digits , choose “234” and “11111” There is no essential difference . 　　 The partition of equivalence class , The most important thing is the division of subsets . actually , Non numbers can continue to be subsets ： Letter , Special characters .

Two 、 Boundary value analysis

　　 Long term testing experience tells us that , A lot of errors occur at the boundary of the input or output range , Not inside the I / O range . Therefore, test cases are designed for various boundary conditions , We can find out more mistakes . Selected test cases , Should be exactly equal to 、 Just bigger than 、 Just less than the boundary value , for example , For the interval min,max Value , Test cases can be recorded as min,min+,max,max-. 　　 for example , Assume X Integers ,10≤X≤100, that X The boundary value that should be taken in the test is ：10,11,99,100. 　　 notes ： It's just boundary values , If it is a complete test , In addition to boundary values , A normal value is also required , namely 12-98 Any value between . 3、 ... and . Wrong guess 　　 Miscalculation refers to ： When testing a program , People can infer from experience or intuition that there may be various errors in the program , So as to write a method to check these error test cases . 　　 This method has no fixed form , Rely on experience and intuition , A lot of times , We all use it unconsciously .

3、 ... and 、 A false assumption

　　 Miscalculation refers to ： When testing a program , People can infer from experience or intuition that there may be various errors in the program , So as to write a method to check these error test cases . 　　 This method has no fixed form , Rely on experience and intuition , A lot of times , We all use it unconsciously .

Four 、 Decision table method

　　 Also known as policy table , Policy table based testing , It is the most rigorous test method in functional testing . This method is suitable for logic judgment of complex scenes , The results are obtained by exhaustive conditions , Then optimize and merge the results , You will get a clearly judged strategy table . 　　 for example , A company classifies its customers as follows ： 　　 The amount of each order placed by the customer is 1000 Yuan of above （ contain 1000 element ）, Reputable , Order setting “ first ” sign ; 　　 Bad reputation , But regular customers , Order setting “ first ” sign ; 　　 Bad reputation , But new customers , Order setting “ normal ” sign ; 　　 The amount of each order is 1000 Yuan of the following , Order setting “ normal ” sign . 　　 Decision table drawn 　　 This table is divided into two lines , Two columns , Use different colors to distinguish . 　　 Light blue ： List all conditions （ Or input ） 　　 light gray ： List all results （ Or output , Action or decision ） 　　 light yellow ： Enumerate the combinations of all conditions 　　 Light green ： According to the conditions of each column , Judge the result 　　 Because all the conditions are exhausted , So it can be said that this judgment is 100% Correct . The next step is to merge and optimize this table . 　　 for example , From the number 1,2 You can see , Customer orders >=1000, Good reputation , Whether new or old customers , Set as priority , So the above tables are consolidated , Get the following table

such , We can get a clearer logical judgment , It can also better assist us in writing test cases . And the decision table , It's also useful for developers . 　　 From the table above , We can write more concise judgment sentences .

5、 ... and . Orthogonal experiment

　　 Using language to describe orthogonal experiment method will be very abstract and difficult to understand , In short , That is, when the factors are independent of each other , Design a special form , Find a few test cases that can replace a comprehensive test case . 　　 among , The special table mentioned above is an orthogonal table , Is a table generated according to certain rules . 　　 Although it is a special form , The actual form of expression is no different from the general form , The main feature of orthogonal table is ,“ Uniform distribution , Be neat and uniform ”, Precisely because “ uniform ” Of , So we can replace all with a few . 　　 for example ： 　　 The communication department of a university has 2 A class , Just finished a course , Want to pass “ Gender ”、“ class ” and “ achievement ” These three query conditions have an impact on the score distribution of this course in the Department of communication , The proportion of men and women or the proportion of classes . 　　 In the traditional way , We will enumerate all combinations , To write test cases , The number of combinations is 2*2*2=8. 　　 See the table below for the arrangement and combination

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Reference from ： Several common design methods of test cases

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