Summary of interface automation interview questions for software testing

One How do you do interface testing ？

In general , Go through the following process ： Interface requirements survey 、 Interface test tool selection 、 Interface test case writing 、 Interface test execution 、 Interface test regression 、 Continuous integration of interface test automation . say concretely , The interface test process is divided into the following nine steps ：

First step ： Analyze the test requirements , And please provide the interface description document ;
The second step ： Sort out the interface test cases from the interface description document , It should include detailed input parameters （ Normal condition , Exceptions include the number of input parameters , type , Optional / Mandatory , Consider the case where the parameters are mutually exclusive or associated ） And out parameter data （ Meet the requirements of interface documents ） And clear formats and checkpoints ;
The third step ： Review interface test cases with development ;
Step four ： Combined development library , Prepare the input parameter data and output parameter data in the interface test case , And organize them into Excel File format ;
Step five ： Combine interface test case documents and Excel Data document in format , Write the business logic code of interface automation test ;
Step six ： Start executing interface automation test cases ;
Step seven ： Execution, if any bug, Submit to defect management platform ;
Step eight ： After development and modification , Return to bug, Tracking status ;
Step nine ： Automatic continuous integration after completion ;

Two How to design test cases for interface testing ？

The interface use cases are designed from four aspects ： function , Business logic , abnormal , Security .

function ： Does it meet the requirements

1） From the user's point of view, whether the interface can meet the business requirements , Whether the function is normal ;

2） Whether the function is implemented according to the interface document ;

give an example ： For example, add essays to the blog Garden , Login is required to add . That is, the business requirements do not support tourists to add essay function , If you design a user who doesn't log in , Then test and add the essay interface , The result interface can be added to the essay , It indicates that the function is abnormal , Non conformance with requirements and interface document description .

Business logic ： Whether it depends on the business

1） Interface implementation logic ;

2） Business logic coverage （ sentence / Conditions / Branch / determine /…）;

give an example ： Before the interface call , The login interface needs to be called , If you don't log in, you can request data , Not in line with business logic .

abnormal ： Parameter exception and data exception

1） Parameter exception ： Key parameters , The parameter is empty. , many , Less parameters , bad parameter ;

2） Data exception ： Keyword data , Data is empty , The length is not the same , Wrong data ;

give an example ： Whether data exception or parameter exception , The test points are similar , One parameter is key and value,key Said parameters ,value According to the data . First of all , See if the parameters and data can support keywords , for example Java Reserved keywords in ; The second is that the parameters and data are empty , See if you have made a judgment ; Third , More and less parameters , For example, an interface with two parameters , You need to design a use case with three parameters , A use case with only one parameter . Inconsistent data length , For example, whether designing long strings supports , Because the length of each field is set in the database table creation process . Enter wrong parameters and data , Such as deliberately typing wrong words, etc .

Security test case design ：

1)cookie： Yes cookie To get the data , If not cookie And then there's the message back , Explain that there is a problem ;
2)header： Normal interface belt header Information , Delete header See if you can return data ;
3) Unique identification number ：app Cell phone identification number , The only thing is that ;

4) Text input box sql Injection and xss attack .

3、 ... and Do you need to compare databases during interface test execution ？

The returned key fields and field values of the interface need to be verified , Otherwise, interface testing is meaningless .
There are generally two ways ：

1） Database preset data , Interface verification returns ;

2） Interface call , Compare database query results .

Four What is the quality evaluation standard of interface test ？

Generally speaking , Evaluate from the following eight aspects ：

1. Whether the business function coverage is complete ;
2. Whether the business rule coverage is complete ;
3. Parameter verification whether the requirements are met （ The border 、 Business rules ）;
4. Whether the interface exception scenario coverage is complete ;
5. Whether the interface coverage meets the requirements ;
6. Whether the code coverage meets the requirements ;
7. Whether the performance index meets the requirements ;
8. Whether the safety indicators meet the requirements ;

5、 ... and How to clean up the garbage data generated by the interface

Creating data and data cleaning , need Python It's connected to the database , Do the operation of adding, deleting, modifying and checking, test case pre operation .

setUp Do data preparation and post operation ;
tearDown Do data cleaning ;

6、 ... and For other interfaces, the interface information shall be obtained first , How to make the logged in interface call only once in other interfaces ？

The solution is as follows ：

Use singleton mode ;
Use a custom caching mechanism ;
Use... In the test framework setup Mechanism ;
pytest in fixture Mechanism ;

7、 ... and How to design interface test assertion ?

Interface test assertions can be designed from the following five aspects ：
1） Response code ： Check whether the response code is as expected , Used to judge whether the test case is executed successfully （ in the light of http Interface ）;

2） keyword ： Verify that the keyword meets expectations , Used to judge whether the test case is executed successfully ;

3） Regular matching ： When an interface returns more content , And there are certain rules , Regular expressions can be used to verify the information returned by the interface to determine whether the test case is successfully executed ;

4） Database matching check ： For example, when verifying the data returned by querying an interface , By writing sql Statement query results , And then sql After the statement is executed, the result returned by the database is checked with the result returned by the interface , To determine whether the test case is successfully executed ;

5） Auxiliary verification through relevant interfaces ： such as , When testing a delete interface , After deleting a record , Want to verify that this record was really deleted , The query interface can be called , If the deleted record is not found , It indicates that the record is deleted successfully .

8、 ... and How to test interfaces that rely on third-party data ？

You can use some Mock Tools （ Such as ：JSON Server、Easy Mock） To simulate the data return of a third party , Minimize dependence on third-party data interfaces .Mock Service refers to some complex services during testing （ Or not very well constructed ） The object of , Replace it with a virtual object . If so now A and B Two interfaces , A Need to call interface B To meet the business requirements . This is the time B The interface has the following three situations ：

1）B The interface has not been developed yet ： You need to wait for the data of the interface to develop , At this time, the perfect interface Mock The service can greatly shorten the waiting time for development and joint commissioning .

2）B Some of the scenes are difficult to simulate ： For example, timeout. 、 Unknown error or unstable third-party interface .

3） Isolation during performance testing B Interface ( Third party interface )： There will be problems during the pressure measurement .

Nine API What are the advantages of testing ？

API yes (Application Programming Interface), That is, the application programming interface .API Is a set of disciplines for building software applications , Protocols and tools .API Act as an interface between software applications , And allows two software applications to communicate with each other .API Is a set of software functions , Can be executed by other software .API The test has the following advantages ：

Faster and higher test coverage .
API Testing helps us reduce testing costs . adopt API test , We can do it in GUI Small errors found before testing . stay GUI Testing period , These small mistakes will become bigger . therefore , stay API It will be cost-effective for the company to find these errors in the test .
API Testing has nothing to do with language .
API Testing is very useful in testing core functions . We can test without a user interface API. stay GUI In the test , We need to wait until the application is available to test core functionality .
API Testing helps us reduce risk .

Ten The interface cannot be adjusted , How to investigate ？

The reason why the interface cannot be adjusted ：
1） The interface did not respond

Many times when doing interface testing , You will find that the interface does not return any , For example, the browser has been circling , Or return to a blank page . When using the interface test tool , Tool error , Tips “no response”.

Investigation thought ：

1. Check the interface first ip Whether it is right , This can be done on this machine ping Interface ip, Check if the network is open ;

2. Check whether the port number of the interface is correct , This can be done on this machine telnet Interface ip And port number , Check whether the port can be connected ;

3. Check whether the project is started or deployed successfully , You can find R & D to confirm , Or log in to the server by yourself , adopt ps Command to check whether the process of the project exists , And then use tail Command to view the deployment log ;

4. Check that the server firewall is turned off , If it cannot be closed due to security or permission problems , You need to find the O & M for policy configuration , Open the corresponding ip And port number ;

5. Check your client （ browser / Testing tools ）, Whether the network proxy is set , The network proxy may cause the request to fail ;

6. Check the... Of the operating system host file , Whether an incorrect... Is bound ip mapping ;

2） The interface responded but returned an error status code

Sometimes the interface will return some errors HTTP Status code , The specific cause needs to be determined according to different status codes .

Investigation thought ：

400： Client request error , For example, the request parameter format is incorrect （ Such as json Illegal string ）;

401： unauthorized , Like asking for header in , Lack of necessary headers （ Such as token、auth Etc ）;

403： prohibit , The common reason is that the user's account does not have a corresponding url jurisdiction , There is also the middleware used in the project , Remote access is not allowed （ such as Apache）;

404： Resource not found , There are many reasons for this , such as ：

url Spelling mistakes ;
url After space ;
The project did not start successfully ;
The request agreement is wrong , Such as http/https;
405： Method does not allow , The common reason is that the request method is incorrect , such as GET Type interface , Use POST The way to ask ;

415： Unsupported media types , The common reason is that the type of requested data does not match the type supported by the server , such as json Interface , You need to add a header Content-type:application/json;

500： Server internal error , This happens , It indicates that the server reported an error , You need to log in to the server , Check the error log , Check according to the specific prompt information ;

502/503/504（Bad Gateway/ Wrong gateway 、Service Unavailable/ Service is not available 、Gateway Timeout/ gateway timeout ）. From the following two situations ：

This error will be reported if the interface is called for a single time , This indicates that there is a problem with the back-end server configuration , Or the service is not available , Hang up ;
If this error occurs during concurrent pressure measurement , It means that the rear end pressure is too high , Something unusual happened , This problem is usually caused by long response time or no response at the back end .

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