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tests/unit/test_exceptions_and_middleware.py

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+"""Tests for the exception hierarchy and global exception handlers."""
+
+import pytest
+from fastapi import FastAPI
+from fastapi.testclient import TestClient
+
+from app.exceptions import (
+    AppError,
+    AuthenticationError,
+    AuthorizationError,
+    DuplicateError,
+    NotFoundError,
+    ProviderError,
+    RateLimitError,
+    ValidationError,
+)
+from app.middleware import register_exception_handlers
+from app.schemas.common import APIEnvelope
+
+
+# ── Exception hierarchy tests ──
+
+
+def test_app_error_defaults():
+    err = AppError()
+    assert err.status_code == 500
+    assert err.message == "Internal server error"
+    assert str(err) == "Internal server error"
+
+
+def test_app_error_custom_message():
+    err = AppError("something broke")
+    assert err.message == "something broke"
+    assert str(err) == "something broke"
+
+
+@pytest.mark.parametrize(
+    "cls,code,default_msg",
+    [
+        (ValidationError, 400, "Validation error"),
+        (NotFoundError, 404, "Resource not found"),
+        (DuplicateError, 409, "Resource already exists"),
+        (AuthenticationError, 401, "Authentication required"),
+        (AuthorizationError, 403, "Insufficient permissions"),
+        (ProviderError, 502, "Market data provider unavailable"),
+        (RateLimitError, 429, "Rate limited"),
+    ],
+)
+def test_subclass_defaults(cls, code, default_msg):
+    err = cls()
+    assert err.status_code == code
+    assert err.message == default_msg
+
+
+def test_subclass_custom_message():
+    err = NotFoundError("Ticker not found: AAPL")
+    assert err.status_code == 404
+    assert err.message == "Ticker not found: AAPL"
+
+
+def test_all_subclasses_are_app_errors():
+    for cls in (
+        ValidationError,
+        NotFoundError,
+        DuplicateError,
+        AuthenticationError,
+        AuthorizationError,
+        ProviderError,
+        RateLimitError,
+    ):
+        assert issubclass(cls, AppError)
+
+
+# ── APIEnvelope schema tests ──
+
+
+def test_envelope_success():
+    env = APIEnvelope(status="success", data={"id": 1})
+    assert env.status == "success"
+    assert env.data == {"id": 1}
+    assert env.error is None
+
+
+def test_envelope_error():
+    env = APIEnvelope(status="error", error="bad request")
+    assert env.status == "error"
+    assert env.data is None
+    assert env.error == "bad request"
+
+
+# ── Middleware integration tests ──
+
+
+def _make_app() -> FastAPI:
+    """Create a minimal FastAPI app with exception handlers and test routes."""
+    app = FastAPI()
+    register_exception_handlers(app)
+
+    @app.get("/raise-not-found")
+    async def _raise_not_found():
+        raise NotFoundError("Ticker not found: XYZ")
+
+    @app.get("/raise-validation")
+    async def _raise_validation():
+        raise ValidationError("high < low")
+
+    @app.get("/raise-duplicate")
+    async def _raise_duplicate():
+        raise DuplicateError("Ticker already exists: AAPL")
+
+    @app.get("/raise-auth")
+    async def _raise_auth():
+        raise AuthenticationError()
+
+    @app.get("/raise-authz")
+    async def _raise_authz():
+        raise AuthorizationError()
+
+    @app.get("/raise-provider")
+    async def _raise_provider():
+        raise ProviderError()
+
+    @app.get("/raise-rate-limit")
+    async def _raise_rate_limit():
+        raise RateLimitError("Rate limited. Ingested 42 records. Resume available.")
+
+    @app.get("/raise-unhandled")
+    async def _raise_unhandled():
+        raise RuntimeError("unexpected")
+
+    return app
+
+
+@pytest.fixture
+def client():
+    return TestClient(_make_app())
+
+
+def test_middleware_not_found(client):
+    resp = client.get("/raise-not-found")
+    assert resp.status_code == 404
+    body = resp.json()
+    assert body["status"] == "error"
+    assert body["data"] is None
+    assert body["error"] == "Ticker not found: XYZ"
+
+
+def test_middleware_validation(client):
+    resp = client.get("/raise-validation")
+    assert resp.status_code == 400
+    body = resp.json()
+    assert body["status"] == "error"
+    assert body["error"] == "high < low"
+
+
+def test_middleware_duplicate(client):
+    resp = client.get("/raise-duplicate")
+    assert resp.status_code == 409
+    body = resp.json()
+    assert body["status"] == "error"
+    assert "already exists" in body["error"]
+
+
+def test_middleware_authentication(client):
+    resp = client.get("/raise-auth")
+    assert resp.status_code == 401
+    body = resp.json()
+    assert body["status"] == "error"
+
+
+def test_middleware_authorization(client):
+    resp = client.get("/raise-authz")
+    assert resp.status_code == 403
+    body = resp.json()
+    assert body["status"] == "error"
+
+
+def test_middleware_provider_error(client):
+    resp = client.get("/raise-provider")
+    assert resp.status_code == 502
+    body = resp.json()
+    assert body["status"] == "error"
+
+
+def test_middleware_rate_limit(client):
+    resp = client.get("/raise-rate-limit")
+    assert resp.status_code == 429
+    body = resp.json()
+    assert body["status"] == "error"
+    assert "42 records" in body["error"]
+
+
+def test_middleware_unhandled_exception():
+    app = _make_app()
+    with TestClient(app, raise_server_exceptions=False) as c:
+        resp = c.get("/raise-unhandled")
+    assert resp.status_code == 500
+    body = resp.json()
+    assert body["status"] == "error"
+    assert body["data"] is None
+    assert body["error"] == "Internal server error"