API Testing

What is an API?

API is an acronym for Application Programming Interface.

The approach of API Testing:

Following points helps the user to do API Testing approach:

1. Understanding the functionality of the API program and clearly define the scope of the program
2. Apply testing techniques such as equivalence classes, boundary value analysis, and error guessing and write test cases for the API
3. Input Parameters for the API need to be planned and defined appropriately
4. Execute the test cases and compare expected and actual results.

How to do API Testing

API testing should cover at least following testing methods apart from usual SDLC process

• Discovery testing: The test group should manually execute the set of calls documented in the API like verifying that a specific resource exposed by the API can be listed, created and deleted as appropriate
• Usability testing: This testing verifies whether the API is functional and user-friendly. And does API integrates well with another platform as well
• Security testing: This testing includes what type of authentication is required and whether sensitive data is encrypted over HTTP or both
• Automated testing: API testing should culminate in the creation of a set of scripts or a tool that can be used to execute the API regularly
• Documentation: The test team has to make sure that the documentation is adequate and provides enough information to interact with the API. Documentation should be a part of the final deliverable

Challenges of API Testing

Challenges of API testing includes:

• Main challenges in Web API testing is Parameter Combination, Parameter Selection, and Call Sequencing
• There is no GUI available to test the application which makes difficult to give input values
• Validating and Verifying the output in a different system is little difficult for testers
• Parameters selection and categorization is required to be known to the testers
• Exception handling function needs to be tested
• Coding knowledge is necessary for testers