Override a FastAPI dependency at the APIRouter level
Tests FastAPI DI scoping limits. Answer: APIRouter has no dependency_overrides; create a sub-app, apply overrides, mount it. Red flag: Claiming router-level overrides exist or mutating global app state.
What it tests: Deep knowledge of FastAPI's dependency injection boundaries. Answer outline: First, APIRouter does not expose dependency_overrides; only FastAPI app instances do. Second, create a dedicated sub-application, register the router there, set sub_app.dependency_overrides to the mocked dependency, and mount the sub-app under the main application. Third, this isolates the override because the sub-app maintains its own DI container.
Read the original → fastapi.tiangolo.com
- #fastapi
- #dependency-injection
- #python
- #api-router
- #testing
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