🧪 Add test for Pydantic schema ref attributes

tests/test_schema_ref_pydantic_v2.py

@@ -0,0 +1,72 @@
+import sys
+
+from fastapi import FastAPI
+from fastapi.testclient import TestClient
+from inline_snapshot import snapshot
+
+from tests.utils import skip_module_if_py_gte_314
+
+if sys.version_info >= (3, 14):
+    skip_module_if_py_gte_314()
+
+from pydantic import BaseModel, ConfigDict, Field
+
+app = FastAPI()
+
+
+class ModelWithRef(BaseModel):
+    ref: str = Field(validation_alias="$ref", serialization_alias="$ref")
+    model_config = ConfigDict(validate_by_alias=True, serialize_by_alias=True)
+
+
+@app.get("/")
+async def read_root() -> ModelWithRef:
+    return ModelWithRef(ref="some-ref")
+
+
+client = TestClient(app)
+
+
+def test_get():
+    response = client.get("/")
+    assert response.json() == {"$ref": "some-ref"}
+
+
+def test_openapi_schema():
+    response = client.get("openapi.json")
+    assert response.json() == snapshot(
+        {
+            "openapi": "3.1.0",
+            "info": {"title": "FastAPI", "version": "0.1.0"},
+            "paths": {
+                "/": {
+                    "get": {
+                        "summary": "Read Root",
+                        "operationId": "read_root__get",
+                        "responses": {
+                            "200": {
+                                "description": "Successful Response",
+                                "content": {
+                                    "application/json": {
+                                        "schema": {
+                                            "$ref": "#/components/schemas/ModelWithRef"
+                                        }
+                                    }
+                                },
+                            }
+                        },
+                    }
+                }
+            },
+            "components": {
+                "schemas": {
+                    "ModelWithRef": {
+                        "properties": {"$ref": {"type": "string", "title": "$Ref"}},
+                        "type": "object",
+                        "required": ["$ref"],
+                        "title": "ModelWithRef",
+                    }
+                }
+            },
+        }
+    )