After reading this article, you should thoroughly understand how to do interface testing

Common project architecture

What is an interface

Interface ： A unified access method provided by the server program , Usually used HTTP agreement , Through different url, Different request types （GET、POST）, Different parameters , To execute different business logic .

Most of the business operations of the client , All need to call the server interface to obtain some data , Or trigger some business , Then the client gets the data returned by the interface , It will do different processing and display according to the data content .

Why do interface tests

A、 In the company , The client and server are usually developed by different teams , In the process of project development , The progress of client and server development is inconsistent , For example, the server is developed first , At this time, you can test the interface of the server first , Ensure that the server logic and return The back data is correct , Then test the client . Or some testing department , Dedicated test server development team , therefore , Their test object is the interface .

B、 When testing certain businesses , You can't just test through the front end , For example, user registration , The front end restricts that the user name cannot be empty , But some people may use tools to bypass the front end and call the server interface directly , If the server does not make relevant logical judgment , Will cause data error . Including whether key information is encrypted during interface data transmission . Therefore, the server interface must be tested separately .

C、 After development and test , You can run the interface test of the server through the tool first , Ensure that all interface test cases pass , Quickly judge whether the server interface meets the expectations . And then through UI Test the interface . Otherwise, the interface has bug, The front page must have bug.

Interface test tools and processes

common HTTP Interface testing tools include Jmeter、Postman、SoupUI etc. . What is used more in enterprises Jmeter.

Jmeter It's an open source 、 Free interface testing tools , It can control the function of the interface 、 Performance testing . Interface automation can also be realized .

Jmeter Specific use , Please refer to 《Jmeter Interface tool practice 》 file

Interface test process ：

And ordinary web The test is the same , It is also a requirement analysis first 、 Test case writing 、 Perform the test 、 Submit bug、 regression testing 、 Submit Test report, etc .

The focus of interface testing

1、 Input

Input mainly refers to the input parameters of the interface , In our usual tests , Will consider the normal input first , And abnormal input parameters , Exceptions include ： Parameter exception and data exception , Use case design uses equivalence class partition and boundary value analysis

Normal input parameters

Normal input parameters are well understood , It is based on the input standard of the interface design document , Enter normal parameters , Respond according to the interface design document Return to normal under certain conditions

Parameter exception

Parameter exceptions include ： The parameter is empty. , More or less participation , Wrong parameters

Data exception

Data exception ： Wrong data type 、 Non null parameter is null , The length does not conform to the design , Out of range data , Illegal members , special Characters or sensitive characters , Abnormal parameter data with associated relationship, etc

2、 Business logic

And based on UI The same as the functional test , Interface testing also needs to understand the business logic behind the interface , Processing logic for business processes , We You can enter parameter constraints from 、 The action object of the event 、 Business state transition and other different dimensions

Analysis of constraints

① Numerical limits ： Dictionaries , Grade , Industry related restrictions , Amount limit , Score limits, etc

② The limitation of state ： It works | Invalid , On-line | offline , Pull black | Wash white, etc

③ Relationship constraints ： Exist or not exist , Bind or unbind, etc

④ Limits of authority ： Administrators , Ordinary users, etc

Object analysis

Object analysis is mainly used to operate legal and illegal objects , For example, bank card users recharge their cards , There may be ： user A Use non users A Recharge your card ; user A Recharge with your own card , The card has expired ; user A Recharge with your own card , The card is blacklist or loss report, etc .

Analysis of state transition

Such as payment business , Pay first , There will be a refund after cancellation , Pay again if payment is unsuccessful , Payment failure , Between states Whether the switching is normal , Failure to operate smoothly according to normal business , How does the status display , Is it controllable , Whether there is an abnormal state , Empty state How to deal with business, etc

Timing analysis

In some complex activities , An activity consists of a series of actions in a specified order , These actions form an action flow , Yes, in this order , To wait until the expected results , What will the program do with other branch actions that occur during execution ？

3、 Output

When considering exceptions , Usually we think of the normal situation , Invalid situation , But it may not cover all error codes , The error code returned by the interface definition can help us supplement the use cases in this part , For example, the network is abnormal , Invalid rule , Invalid parameter , Invalid business ID, Invalid task , Server exception, etc , hold errorcode More use cases can be designed by adding the values of

The design of use cases based on the output , You can find out whether the front and rear ends output results normally , Whether the prompt is friendly , Prompt whether sensitive information appears, etc

4、 Database operation

Whether business data warehousing is normal , Whether there is duplicate data warehousing , Whether there is garbled code

Whether the data update is normal , Especially the time field , Whether the time is 24 The hour format

Whether the fields in the table meet the expectations

5、 Security

Whether sensitive information is encrypted （ Such as user name 、 Bank Account , password , Transfer amount ）

6、 performance

The maximum number of concurrency supported by the interface

How many services can the interface handle per second （TPS）

The average response time of the interface （RT）

The consumption of server resources by the interface （CPU、 Memory 、 The Internet 、 disk ）

7、 Compatibility

Interface testing does not need to consider the compatibility of the client , Mainly data compatibility . For example, whether the historical data of the old interface is compatible , use New interfaces to handle old data , Whether it can be handled normally .

8、 other

Idempotency ： It means that the result of one or more requests for the same operation is consistent , It won't have side effects due to multiple clicks .

Let's take the simplest example ：

That's payment , Users pay after they buy goods , Payment and deduction succeeded , But when the result is returned, the network is different often , At this time, the money has been deducted , The user clicks the button again , At this point, the system should refuse to pay , And prompt “ You can't pay repeatedly ”. amount to The second payment will have no effect . When doing interface tests , For some interfaces with idempotent requirements , You need to test idempotent try .

It is usually possible to use Jmeter Continuous call 2 Secondary interface for payment 、 Submit and other operations , To test idempotency .

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