Which of the following is NOT a challenge faced in API testing?

• A. Output verification and validation
• B. Parameter Selection
• C. Testing graphical user interfaces
• D. Call sequencing

Answer: (C)

Testing graphical user interfaces (GUIs) is not typically a challenge encountered in API testing because API testing focuses on interactions at the network level, specifically dealing with requests and responses sent over protocols like HTTP. It assesses the functionality, reliability, performance, and security of APIs by examining the data exchanged rather than the visual components presented to users.

When it comes to output verification and validation, parameter selection, and call sequencing, these are specific considerations essential in API testing. Output verification involves ensuring that the responses returned by the API are accurate and meet the expected results based on the input provided. Parameter selection is critical as it determines which data is sent in requests, impacting the results and the behavior of the API. Call sequencing refers to the correct order or timing in which API endpoints should be called, which is crucial for validating workflows or state-dependent actions. Thus, these elements present challenges that testers must address when evaluating the performance and correctness of APIs.