As for the white box test, you have to be skillful in these skills~

For many small partners who are just beginning to learn software testing , If you can get the black box as soon as possible 、 White box test to understand , Master the conclusions and basic principles of the two tests , It will be helpful to my later study . today , Let's talk about black boxes 、 Topics related to white box testing .

1、 Black box test method and summary

The most common black box test methods include ： The boundary value 、 Equivalence class 、 Wrong guess 、 Scene method 、 Cause and effect diagram 、 Decision table composition method 、 Orthogonal experimental design . Take a few examples ：

Boundary value test ： Boundary value testing is one of the most basic black box testing methods , It is “ Equivalence class division ” A good complement to this test method . But this method also has disadvantages —— A lot of redundancy and vulnerabilities . in addition , Because the Boolean content does not have the concept of boundary , So boundary value tests are not valid for Booleans .

Equivalence class testing ： Equivalence tests are mainly divided into 【 Weak equivalence class test 】 and 【 Strong equivalence class test 】. This kind of test is mainly used to solve Boolean and logical problems . When doing this kind of test , It is suggested that after the equivalence class is divided , Number each equivalent class , In this way, the conclusion and operation steps may look clearer .

Cause and effect diagram ： The causality diagram method mainly involves the test of causality , When writing test cases , We need to make a clear distinction “ Identity 、 or 、 Not ” Relationship , It is also necessary to distinguish between various constraints . Cause and effect diagram can be used to describe the relationship between input and output . But the drawing process is rather tedious . Cause and effect diagram can be transformed into decision table . It is recommended that during the test , Try to draw the decision table directly .

（ such as ：E constraint ( different ; Exclusive or )：a,b At most one may be 1, You can't do it at the same time 1;

I constraint ( or ; contain )：a,b,c At least one of the must be 1, You can't do it at the same time 0;

O constraint ( Only )：a and b One and only one must be 1;

R constraint ( requirement )：a yes 1 when ,b Must be 1, namely a by 1 when ,b Not for 0;

M constraint ： Constraints on output conditions , If it turns out a by 1, Then the result b It has to be for 0）

Decision table test ： It is only suitable for analyzing input fields , It is not suitable for testing the output domain .

Wrong guess ： The advantage of this method is that it can give full play to the experience and potential of testers , High hit rate ; The disadvantages are also very obvious , It is difficult to guarantee coverage .

in addition , Test cases designed by black box test method , There may be vulnerabilities and redundancy , But in general , It is difficult for testers to evaluate it . therefore , Testers can also use the coverage index of white box test , To measure the vulnerability and redundancy of black box testing methods .

2、 Method and summary of white box test

The method of white box test is relatively simple , There are two main categories .

One is static testing . This kind of testing mainly focuses on source code inspection and optimization . The basic test method is that there is no need to design test cases , Just view the source code and simulate the execution code . By putting forward the opinions on structural design optimization and suggestions on key test points , Can complete the corresponding test work .

The other is dynamic testing . This kind of testing mainly focuses on the testing of key program structures , Its basic test method is to determine the complexity of the program structure through the expression 、 Execution path and loop structure , To design corresponding test cases . So as to achieve a certain degree of test coverage , Ensure test completeness and no redundancy of the test .

that , What are the typical test methods for these two types of tests ？

A typical method of static testing is ： Peer review 、 Static structure analysis 、 Code quality measurement and data flow testing of variables . There are many methods of dynamic testing , Include ： Decision test based on logical expression coverage index ; Independent path testing based on full path coverage ; And the test of the loop based on the coverage of the loop process .

3、 The comprehensive strategy of white box testing

In daily life , We usually use black box test method , Use the white box test as an aid , Additional testing and code optimization .

This is mainly because white box testing is a test for program code , Testers need to understand the details of program implementation , The technical requirements for the personnel who design and perform the test are high . If novice testers want to improve their abilities , After entering the industry , Learn more about the white box test .

The content based on black box test is relatively easy to understand , below , Let's do the white box test , Talk about how to use a comprehensive strategy , To test the project . here , We mainly recommend these comprehensive strategies ：

1） Give priority to static white box test .

Especially when testing the core code of functional modules , Be sure to organize strict reviews regularly , And through experience summary , Constantly update test standards or normative documents such as defect checklists , Make the test rigorous .

2） Pay attention to extracting test data with boundary .

When designing test cases , Be sure to combine logic to determine the boundary of the expression 、 The boundary of the number of cycles 、 Boundary of variable value range, etc , To comprehensively test , Avoid missing test .

3） Make more use of the white box test method for supplementary tests .

Especially where the black box test cannot or is difficult to check （ Such as memory leak ）, Try to use a special white box test method （ Such as memory leak test ）, Conduct supplementary tests .

4） For key variables , Use the data flow test method to determine the focus of the supplementary path test .

5） Try to use testing tools to complete the relevant analysis and evaluation of code structure and quality , Design review and optimization of code .

6） Learn from the test method of independent path , Design high-level test cases , Improve test coverage , Reduce test redundancy .

At the end

For testers , Whether we are in the introductory stage of learning 、 Just entering the working stage 、 There are still several years of work , Be sure to learn the contents of black box and white box test thoroughly , At the same time, we will continue to overcome the test content of each sub field , Let oneself have stronger professional ability , Pave the way for your future career ~

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