import importlib import sys from typing import Any import pytest def test_optional_imports_broken_installation(monkeypatch: pytest.MonkeyPatch) -> None: """ Test that an ImportError during the import of an optional JSON library (like orjson or ujson) does not crash the entire fastapi.responses module. """ real_import_module = importlib.import_module def fake_import_module(name: str, package: str | None = None) -> Any: if name in ("ujson", "orjson"): raise ImportError(f"simulated binary/load failure for {name}") return real_import_module(name, package) monkeypatch.setattr(importlib, "import_module", fake_import_module) import fastapi.responses # Force a reload to ensure the module initialization runs with our monkeypatch try: importlib.reload(fastapi.responses) finally: # Revert the monkeypatch manually early so we can restore the module monkeypatch.undo() # Restore test isolation by reloading the module cleanly importlib.reload(fastapi.responses)