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name: fastapi-tdd description: Expert guide for Test-Driven Development in FastAPI, focusing on the "Quads" strategy and async testing patterns. version: 1.0.0 allowed-tools: "Read,Write,Bash"

FastAPI TDD Standards

1. The Strategy: Testing by Layer (The Quads)

Do not write generic tests. Identify the layer and apply the specific strategy: Read({baseDir}/references/quad_strategy.md)

2. Async Testing Rules

• Client: Use httpx.AsyncClient with ASGILifespan.
• Event Loop: Never use TestClient (sync) for async database routes to avoid event loop conflicts [16].
• Overrides: Use app.dependency_overrides to mock Infrastructure layers when testing Presentation layers [17].

3. Scaffolding

To generate a test file structure that mirrors the source code, run: python {baseDir}/scripts/scaffold_test.py <path_to_source_file>