Method of designing test cases

Catalog

One 、 Design test cases according to requirements

Two 、 Specific methods of designing test cases

1. Equivalence class

2. The boundary value

3. Cause and effect diagram

4. Orthogonal method

5. Scene method

6. Wrong guess

3、 ... and 、 How to evaluate the quality of test cases

---

One 、 Design test cases according to requirements

Verify the correctness of the requirements .

Analyze requirements , Refine requirements , Extract functional modules from requirements , Divide sub functions , Write test cases according to sub functions .

Two 、 Specific methods of designing test cases

1. Equivalence class

Put the input （ Output is considered only in special cases ） It is divided into several equivalent classes , Select a representative test case from each equivalent class to test , If this test case passes the test , Let's say that the equivalence class represented by this test case passes .

Effective equivalence class ： According to the requirement specification , Meaningful input data set , Become a valid equivalence class ;

Invalid equivalence class ： Not meeting the requirements ;

In order to solve the problem of too many test cases , Enter situations that cannot be exhausted .

2. The boundary value

Design test cases according to the boundary of input and output .

3. Cause and effect diagram

Cause and effect diagram is a kind of logic diagram （ Identity 、 And 、 or 、 Not ）, When there are many inputs , Different combinations of inputs correspond to different outputs , Use cause and effect diagram to analyze the relationship between different input combinations and different outputs .

The steps of designing test cases by causality diagram ：

① Analyze all inputs and outputs ;

② Find out the relationship between input and output ;

③ Draw a cause and effect diagram according to the relationship between input and output ;

④ According to the causal picture judgment table ;

⑤ Design test cases according to the decision table .

Cause and effect diagram example ：

4. Orthogonal method

An experiment that studies multiple factors and levels （ test ） Method , According to orthogonality , Select the best combination from the input combination for test , The results of the analysis , Analyze the results of this test through the test results obtained from these optimal combinations .

factors ： Input variables ;

level ： Value of variable ;

Composition of orthogonal table ：

① Column ： Factor number （ Number of variables ）

② Horizontal number ： The maximum number of values of each variable

③ That's ok ：L=（ Horizontal number -1）* Factor number +1

Properties of orthogonal table ：

① The number of different data in each column is the same

② The combination of any two columns of different data occurs the same number of times

Orthogonal table design test case steps ：

① Identify all inputs （ Variable ）;

② Determine the number of values of each variable ;

③ Number of determining factors （ Columns of orthogonal table ）, Horizontal number ;

④ According to the properties of orthogonal table , Map the values of variables to the table ;

⑤ Write test cases , Each row of the orthogonal table is a test case ;

⑥ Add test cases that are not in the orthogonal table but that you think may appear .

example ：

full name 、 mailbox 、 password 、 Confirm the password 、 Verification Code , Only consider filling or not filling .

①②③ Factor number =5; Horizontal number =2; Columns of orthogonal table = Factor number =5; Row of orthogonal table =（ Horizontal number -1）* Factor number +1=6

④ Orthogonal table ：

⑤ Write test cases according to each line  

⑥ Add ： Fill in all or nothing .

5. Scene method

Design test cases according to scenario method ： Put forward each function point in the scene , Consider the possible different situations of function points , Design test cases according to these situations . for example ：ATM ATM .

6. Wrong guess

According to the tester's knowledge , Experience , Intuitively judge which module will have problems , Write test cases specifically for this module , As a supplementary test case method .

3、 ... and 、 How to evaluate the quality of test cases

1. Use cases are clearly expressed , No ambiguity ;

2. The use case has strong operability ;

3. The input and output of use cases are clear , A use case has only one expected result ;

4. The maintainability of use cases is good ;

5. Use cases have high coverage of requirements ;

6. Exposure procedures BUG Your ability is strong .