What is the difference between API Testing and Unit testing?

 

A certain type of behavior is reflected by API, which is considered to be a library, that can be included in the code. For example, compatible bytecodes are shared by using a Java API in Scala. API testing focuses on obtaining a logically correct result. When it comes to unit testing, it ensures that each of the units is being tested as per the specific functional requirements. In this article, you will get to know the differences between API testing and unit testing.

What is Application Programming Interface (API) testing?

API provides a platform through which two software systems can communicate effectively. API  testing is a testing process wherein APIs are assessed both as part of integration testing and even independently. This is done to know, if it can fulfill performance, reliability, functionality and security requirements.

Following are a few key points that need to be taken into consideration:

l  It focuses and works on the system under test

l  The entire system as a whole is represented by API testing

l  When the build is complete then after API tests are being run.

 

What is Unit testing?

It is a testing method wherein individual modules or components of an application known as “units” are tested. The units are tested based on specific requirements. It can be carried out either manually or automatically. Following are a few key points that need to be taken into consideration:

l  The code base is comprehended by developers and changes are carried out quickly

l  The code is correct or not is ascertained

l  Cost and time are saved, as bugs are fixed in the initial stages of the software development process

l  Unit testing can be conducted both manually and in automated mode.

 

Differences between API testing and unit testing:

API testing	Unit testing
The testing of functionality takes place from beginning to end, including features and the entire product	Individual testing of functionalities takes place
The testing process is quite difficult, as it involves applications and multiple systems and is carried out by the QA team	It is less complicated when compared to API testing, as the code is tested in the early stages of development by developers
The system’s main functionality is accessed, which is employed by the end-user. It is tested from a user’s standpoint and is considered to be quite comprehensive	Each unit is tested to ascertain, whether it is working as per the required expectations or not
It is a Black box testing technique	It is a white box testing technique
The testing of the entire API functions takes place	All the edge cases are tested in a well-defined manner
There is a thorough examination of all the functional issues	Testing of the most basic functions is conducted
The scope of testing is broader	The scope of testing is limited
It is run, after the build is finished	It is performed before check-in.

 

Advantages of API testing:

l  Less time is consumed by the API testing process. There is less code involved, which in turn provides fast and comprehensive test coverage

l  Language independence can be experienced, wherein the data exchange is done using JSON or XML

l  The intervention of User Interface (UI) is not required to access applications.

 

Advantages of Unit testing:

l  The quality of code is enhanced as minute defects are identified

l  Documentation is an important aspect of unit testing. When a new developer joins the team, the developer can refer to the documentation and learn about the individual components

l  Each unit is properly verified and tested, so that it can passed on to further stages of testing.

 

Conclusion: If you are looking forward to implementing API testing / unit testing for your specific project, then do get connected with a well-established software testing services company that will provide you with a structured testing roadmap aligned with your project scope and requirements.

About the author: I am a technical content writer focused on writing technology specific articles. I strive to provide well-researched information on the leading market savvy technologies.