Let us understand what is an API first,

API testing a software testing of Application Programming Interfaces (APIs). An API is a piece of code that supports any two applications / platforms to communicate by transferring fields / data. In SDLC, APIs are essential to integrating different software modules and building complex applications.

API testing is associated with testing APIs for their functionality, security, reliability  and performance. It assures that the APIs are working as per the business requirement. API testing can be run manually or by automation.

API testing includes the following steps:

Understanding the API : 

               API testing begins with understanding the functionality of API against the business requirement, which also involves reviewing the API against the API requirement document and understanding the API methodologies, input parameters, types and expected results against the specified requirement.

Testing the functionality of API: 

               The API testing is done by executing the test cases that are created against the requirements specified, whether the API is working as per the business requirements giving the expected results.

Testing the reliability of API: 

API’s have to be tested to verify if the API is able to perform as expected consistently under various scenarios pertaining to different use cases of the application and at all the conditions.

Testing the security of API:

API’s have to be tested for their ability to protect against, unauthenticated and unauthorized access, SQL injection attacks, man-in-the-middle (MITM) attacks, resist penetrations against vulnerabilities, provide appropriate error messages, all the logs captured should be encrypted as the data might be business sensitive.

Testing the performance of API:
API’s  have to perform and be able to handle high volume of requests to perform expected results, with optimized performance to keep the system running and not impact the business at different loads and conditions.    

API testing is an essential aspect of SDLC  as it aids to guarantee that the APIs are functioning as per the business requirements. Despite, like any form of testing, API testing has its own challenges. 

In this blog post, we will consider few of  the frequent API testing challenges and how to handle  the same:

Authentication and Authorization:

A serious challenge while we are performing API testing is authentication and authorization, APIs are always required  to be secured by several authentication methods like OAuth or JWT tokens, which leads to difficulty in testing APIs as we require to have valid credentials to access them, to overcome the challenges like this we can use the tools like Postman which helps us to make the set up easier. 

Testing APIs with various inputs:

Since we have various data types and fields in the modern day software which contains a wide variety of data and validations which are received throughout, testing this is a mandate as it may lead to failure of APIs, but to test the same is a tedious and timeconsuming process. The solution to this is by using automation tools like Selenium or Cypress, which allows us to automate API testing and speedup the test APIs with different data inputs.

Versioning and backward compatibility

Any business module often undergo changes as per the requirement change, the APIs related to the module also have to be changed so to record and to maintain the changes such that the changes don’t break the existing functionality. Version control and backward compatibility is required and to maintain the same in APIs is also challenging at times. To go through the challenges like this we need to usee the version control tools lile Git to manage API versions.

Testing API performance and scalability:

APIs are often used by numerous concurrent users, hence it is essential to make sure that the API are able to handle huge traffic of consumers without any downtime or business impact, to maintain the API performance and reliability and scalability is a big challenge to deal with complex APIs and huge data, so we can use load testing tools like JMeter or Gatling to simulate high performance.

Test case Management and Documentation:

Testing APIs is one of the challenge, maintaining and recording all the test cases which is involved in dealing with complex APIs with multiple parameters, authentication methods and endpoints can be a bigger challenge by itself, to overcome this we can use tools like Swagger to generate API documentation and test case management tools like TestRail to manage API test cases.

In conclusion, API testing is a crucial part of SDLC and it is essential to handle the challenges that come with it, By using the correct strategies and apt tools you can ensure that the APIs are working correctly as per the business requirement and doesn’t break the system effortlessly.    

– Ashwini G R