How is api testing different from regular testing? - api

Question

I don't know about testing but I would like to have a clear picture on how is API testing different from other testing methods.

Answer 1

API testing will not include UI as regular testing have
API testing requires basic networking knowledge such as what is the use of GET, POST, PUT, etc commands used.
API testing includes having knowledge of how various html elements work. For example, If I press a button, what will be the next function call. We need to know how 'button' element works
In API only API functions are tested, but in regular testing all the elements are tested
There are different tools used in API testing. POSTMAN is one of them

Answer 2

In API Testing we test Backend functionality while in Regular testing we check UI + Functional testing.
API Testing is helpful in testing Core Functionality.It helps us to reduce the risks.
Steps to Test API Manually:-
To use API manually, we can use browser based REST API plugins.
a)Install POSTMAN(Chrome) / REST(Firefox) plugin
b)Enter the API URL
c)Select the REST method
d)Select content-Header
e)Enter Request JSON (POST)
f)Click on send
g)It will return output response
Steps to start API Automation using REST

Answer 3

in general API testing is made for not doing many similar actions, when we can easily measure the result.
For example if you app button is not on the right place, it is hard to measure using code.
Another example is when you write a library for collections you can say just once:
CheckIntersect method:
result = mylibrary.getIntersection([1,2,3,4], [3,4,5,6])
if result != [3,4]
postTestError("CheckIntersect [1,2,3,4], [3,4,5,6]" + result.ToString() )
In this case you can easily measure the result, and not have a fear of you can't even find the problem in code.

Answer 4

I would like differentiate API vs. Other Testing instead looking into technical details.
API: Testing point of view the API is so important because, we can prepare independent test cases that are separate files. This makes our test approach relatively simple.
For better understanding, "Web API is typically done as HTTP/REST, nothing is defined, output can be eg. JSON/XML, input can be XML/JSON/or plain data. There are no standards for anything => no automatic calling and discovery."
API is a simple interface using HTTP protocol.
Other Testing:
Other testing like GUI, Regression, Unit, etc. Testing is absolutely essential for any application has to be in user friendly. The end user should be comfortable while using all the components should also perform their functionality with utmost clarity. Different Functional and GUI Testing can refer to just ensuring that the look and feel and Functional usability of the application is acceptable to the user.
Conclusion:
API can be:
Developed by one company, used by another company, and hosted by a third company Such involvement of several companies is a business cases for independent testing of API.
Example: Weather information API Developed and Tested by One & Accessed by many.

Answer 5

General Testing is testing each and every feature of the application from UI like web or mobile .
But,
API Testing is to verify the JSON Request to Server and Response from the Server .
If the application is using API all the content and Features based on the API Response from the Server .
For Example In FB app Profile screen, if the name is wrong ,
you can check from UI that general Testing, The same thing you can
Check it from API Response from the server , like below.
{"name":"Dharma","friends":450}