Which of the following is a common error found in API testing?

• A. Performance issues
• B. Documentation errors
• C. High memory usage
• D. User interface bugs

Answer: (B)

In API testing, documentation errors are indeed a common issue. Such errors can arise when the API documentation does not accurately reflect the behavior of the API, including incorrect endpoints, parameter descriptions, request/response formats, or status codes. This can lead to confusion for developers and testers, as they may implement or test against outdated or incorrect documentation, potentially causing failures in understanding how to correctly interact with the API.

While performance issues, high memory usage, and user interface bugs are relevant concerns in software testing, they mainly pertain to different aspects of application performance or user experience. Performance issues often relate to how the system behaves under load rather than the API's response as defined by its documentation. High memory usage might be more applicable to system resource management rather than API correctness. User interface bugs are specifically tied to graphical elements and user interactions, which do not apply to API testing directly, as APIs do not have a user interface component. Therefore, focusing on documentation errors provides a clear insight into a problem critical to effective API testing.