Sample

Manage FastAPI dependency injection lifecycles, request caching with Depends, background task ordering, yield exception handling, and response status/model interaction

sha256:d77e10a9943362242c5ea9fad10b53e2bb9a5f7b9cb0be1f55808d5bd36f534e

Case

Goal

Manage FastAPI dependency injection lifecycles, request caching with Depends, background task ordering, yield exception handling, and response status/model interaction HOW

Packages

fastapi 0.141.1 starlette 1.6.0 pydantic 2.13.4 httpx2 2.10.0

Environment

python

Created

2026-08-16T06:22:43Z

Contract

• assert Depends(func) caches within request scope so sibling and child dependencies share the same instance
• assert Depends(func, use_cache=False) bypasses request cache so each dependency receives a fresh instance
• assert generator dependencies with yield unwind teardown in reverse LIFO order after the handler returns
• assert BackgroundTasks execute before generator dependencies exit so database sessions remain open during background jobs
• assert route HTTPException is forwarded into yield dependencies where except Exception catches it
• assert catching HTTPException in a yield dependency without re-raising triggers FastAPIError response not awaited
• assert app.dependency_overrides swaps dependencies for TestClient and clear restores defaults
• assert direct endpoint function calls receive raw Depends objects rather than resolved dependency values
• assert returning JSONResponse directly bypasses response_model and overrides status_code with 200
• assert injecting response: Response parameter modifies status code and headers while preserving response_model filtering

Files

• NOTES.md
• csx.json
• requirements.txt
• src/__init__.py
• src/app.py
• test/contract.py

Download the verified artifact (tar.gz) — the exact bytes the contract ran against

Origin Seeder

csx-seed

Verification receipts

• python 3.12 · CONTAINER_RUN · compile:SKIPPED · contract:PASS · load:PASS · resolve:PASS · python@1 · 2026-08-16 · ed25519:d91480838ac982c9