Testing GraphQL APIs Quiz Quiz

Dive into key concepts and effective strategies for testing GraphQL APIs, including query validation, error handling, and schema verification. Enhance your grasp of testing techniques for robust and reliable GraphQL implementations.

1. Identifying Successful GraphQL Query Execution

   When testing a GraphQL API, which HTTP status code and response structure most commonly indicate a successful query that returned data as requested?

   1. 201 status with a 'result' field
   2. 404 status with an empty body
   3. 200 status with a 'data' field in the response body
   4. 400 status with a detailed error message

   Explanation: A 200 HTTP status along with a 'data' field is the standard sign of a successful GraphQL query. Status 404 indicates a resource was not found, which does not align with how GraphQL handles operations. Status 201 is used for resource creation in REST APIs, not typical for GraphQL. A 400 status with an error message signals a client request error, not successful data retrieval.

2. Differentiating GraphQL Errors from REST Errors

   What is a key difference between error reporting in GraphQL APIs and traditional REST APIs when testing for failures?

   1. REST APIs include errors only in the URL path
   2. GraphQL returns errors in the response body, not just via HTTP status codes
   3. GraphQL uses XML for error messages
   4. GraphQL never returns errors

   Explanation: In GraphQL, even with an HTTP 200 status, errors are often included in the response body under an 'errors' field. REST APIs generally rely more on HTTP status codes for error signaling. The idea that REST includes errors in the URL path is incorrect; they are usually reported in the body or headers. GraphQL typically uses JSON, not XML, for errors.

3. Validating the GraphQL Schema Structure

   During the testing of a GraphQL API, which approach allows you to confirm the available operations, types, and fields defined by the schema?

   1. Analyzing HTTP headers for schema structure
   2. Calling random queries and guessing responses
   3. Using only endpoint documentation
   4. Introspection query to retrieve schema details

   Explanation: An introspection query is specifically supported by GraphQL to provide a complete view of its schema, including types and operations. Relying solely on endpoint documentation may miss changes or errors. Guessing responses by calling random queries is inefficient and unreliable. HTTP headers do not contain schema structure information.

4. Mocking Data in GraphQL API Testing Scenarios

   Which scenario best illustrates the use of mocking while testing a GraphQL API?

   1. Returning fixed responses for specific queries without a live backend
   2. Testing with actual production data only
   3. Altering the schema during every test run
   4. Using invalid query syntax intentionally

   Explanation: Mocking in GraphQL testing involves providing predefined responses to queries, allowing thorough testing without depending on a live backend. Using only production data does not involve mocking and can lead to unpredictable results. Altering the schema repeatedly complicates testing and is not a form of mocking. Sending invalid syntax purposely is more related to negative or boundary testing than mocking.

5. Testing GraphQL Query Variables

   When testing a GraphQL API operation that accepts variables, which practice ensures the variables are handled correctly and safely?

   1. Passing variables in a separate JSON object in the request body
   2. Embedding variables directly in the query string
   3. Leaving variables undefined at all times
   4. Placing variables in the request URL parameters

   Explanation: The standard way to provide variables to a GraphQL operation is to include them in a dedicated JSON object in the request body, ensuring they are processed and type-checked. Embedding variables directly in the query disregards GraphQL's variable system. Supplying them as URL parameters is not standard practice. Leaving variables undefined can cause errors or security risks.