"properties": {
                        "detail": {
                            "title": "Detail",
                            "type": "array",
                            "items": {"$ref": "#/components/schemas/ValidationError"},
                        }
                    },
                },
                "ValidationError": {
                    "title": "ValidationError",

def test_optional_list_str_schema(path: str):
    assert app.openapi()["paths"][path]["get"]["parameters"] == [
        {
            "required": False,
            "schema": {
                "anyOf": [
                    {"items": {"type": "string"}, "type": "array"},
                    {"type": "null"},
                ],
                "title": "P",
            },
            "name": "p",
            "in": "query",
        }
    ]

from fastapi import FastAPI

app = FastAPI()


@app.get("/items/", include_in_schema=False)
async def read_items():

from fastapi import FastAPI

app = FastAPI()


@app.get("/items/{item_id}")
async def read_item(item_id):

from typing import Union

from fastapi import Cookie, FastAPI

app = FastAPI()


@app.get("/items/")
async def read_items(ads_id: Union[str, None] = Cookie(default=None)):

from typing import Union

from fastapi import FastAPI, Header

app = FastAPI()


@app.get("/items/")
async def read_items(user_agent: Union[str, None] = Header(default=None)):

            }
        },
        "components": {
            "schemas": {
                "HTTPValidationError": {
                    "properties": {
                        "detail": {
                            "items": {"$ref": "#/components/schemas/ValidationError"},
                            "type": "array",
                            "title": "Detail",
                        }
                    },

from typing import Annotated, Union

from fastapi import FastAPI, Header

app = FastAPI()


@app.get("/items/")
async def read_items(
    strange_header: Annotated[
        Union[str, None], Header(convert_underscores=False)
    ] = None,
):

from fastapi import FastAPI

app = FastAPI()

fake_items_db = [{"item_name": "Foo"}, {"item_name": "Bar"}, {"item_name": "Baz"}]


@app.get("/items/")
async def read_item(skip: int = 0, limit: int = 10):

from fastapi import FastAPI, Request

app = FastAPI()


@app.get("/items/{item_id}")
def read_root(item_id: str, request: Request):
    client_host = request.client.host