What type of assertion is used to validate the response schema?

• A. Schema validation assertions
• B. Response code assertions
• C. Header assertions
• D. Content type assertions

Answer: (A)

The correct answer highlights the specific technique used to confirm that the structure and rules of the response data conform to the predefined schema. Schema validation assertions are designed to check whether the JSON or XML response of an API matches the expected format, including the correct data types, required fields, and any additional constraints defined in the schema.

In using schema validation assertions, a tester can ensure that the API response not only returns the desired data but also adheres to structural integrity. This is crucial when the integrity of the data structure is as important as the actual content, especially in applications that depend on consistent data exchange formats.

In contrast, response code assertions relate to checking that the API returns the expected HTTP status codes, ensuring the API is functioning as intended at a high level, but they do not validate the response structure. Header assertions verify the correctness of HTTP headers in the response, which can be important for things like caching or content negotiation, but these also do not address the data schema. Content type assertions focus on checking the MIME type of the response but again do not delve into the specific structure of the data returned.