all working

tests/test_error_handling.py

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+import json
+from typing import Optional
+
+from fastapi import FastAPI, HTTPException
+from fastapi.testclient import TestClient
+from pydantic import BaseModel, Field
+
+from app.middleware.logging import LoggingMiddleware
+from app.middleware.errors import register_exception_handlers
+
+
+class Item(BaseModel):
+    name: str = Field(..., min_length=3)
+    quantity: int = Field(..., ge=1)
+
+
+def build_test_app() -> FastAPI:
+    app = FastAPI()
+    app.add_middleware(LoggingMiddleware, log_requests=False, log_responses=False)
+    register_exception_handlers(app)
+
+    @app.get("/http-error")
+    async def http_error():
+        raise HTTPException(status_code=403, detail="Forbidden action")
+
+    @app.post("/validation")
+    async def validation_endpoint(item: Item):  # noqa: F841
+        return {"ok": True}
+
+    @app.get("/crash")
+    async def crash():
+        raise RuntimeError("Boom")
+
+    return app
+
+
+def assert_envelope(resp, status: int, code: str, has_details: bool, expected_cid: Optional[str] = None):
+    assert resp.status_code == status
+    data = resp.json()
+    assert data["success"] is False
+    assert data["error"]["status"] == status
+    assert data["error"]["code"] == code
+    assert isinstance(data["error"]["message"], str) and data["error"]["message"]
+    if has_details:
+        assert "details" in data["error"]
+    else:
+        assert "details" not in data["error"]
+
+    # Correlation id in body and header
+    assert "correlation_id" in data and isinstance(data["correlation_id"], str)
+    header_cid = resp.headers.get("X-Correlation-ID")
+    assert header_cid == data["correlation_id"]
+    if expected_cid is not None:
+        assert header_cid == expected_cid
+
+
+def test_http_exception_envelope_and_correlation_id_echo():
+    app = build_test_app()
+    client = TestClient(app)
+    cid = "abc-12345-test"
+    resp = client.get("/http-error", headers={"X-Correlation-ID": cid})
+    assert_envelope(resp, 403, "http_error", has_details=False, expected_cid=cid)
+
+
+def test_validation_exception_envelope_and_correlation_id_echo():
+    app = build_test_app()
+    client = TestClient(app)
+    cid = "cid-validation-67890"
+    # Missing fields to trigger 422
+    resp = client.post("/validation", json={"name": "ab"}, headers={"X-Correlation-ID": cid})
+    assert_envelope(resp, 422, "validation_error", has_details=True, expected_cid=cid)
+
+
+def test_unhandled_exception_envelope_and_generated_correlation_id():
+    app = build_test_app()
+    client = TestClient(app, raise_server_exceptions=False)
+    resp = client.get("/crash")
+    # Should have generated a correlation id and not echo None
+    assert_envelope(resp, 500, "internal_error", has_details=False)
+    assert resp.headers.get("X-Correlation-ID")
+
+