api-testing-and-validation-skilllisted

# API Testing and Validation Skill ## Purpose This skill ensures an API or feature is fundamentally indestructible before going to production. It mandates an ultra-deep understanding of the feature's logic, complete mapping of success and failure flows, and a rigorous simulation of every conceivable edge case, culminating in a "Total Mockup Report." --- ## PHASE 0: Deep Knowledge Acquisition Before testing or executing any API calls, you MUST acquire an ultra-deep understanding of how the feature works. 1. **Read the Source Code**: Trace the exact logic from Controller -> Service -> Repository/DB. 2. **Understand the Contracts**: Analyze request DTOs, response DTOs, Headers, and Authentication requirements. 3. **Map the Dependencies**: What third-party APIs, queues, or caches does this feature rely on? --- ## PHASE 1: Flow Mapping & Test Case Generation You must map out EVERY possible scenario. Do not stick to the "happy path." ### 1. Success Flows (Happy Path) - Standard execution with typical payloads. - Responses must match exact expected schema. - Status codes must be strictly compliant (e.g., 200 OK, 201 Created). ### 2. Failure Flows (Unhappy Path) - Invalid payloads (missing fields, wrong types). - Unauthorized / Unauthenticated requests (401, 403). - Not Found scenarios (404). - Dependency failures (Database timeout, third-party API 5xx errors). ### 3. Edge Cases & Malicious Input (Deep Down Check) - **Boundary Testing**: Maximum length strings, extremely larg