class OtherItem(BaseModel):
        value: Literal["other"]
        price: float

    Item = Annotated[
        Union[Annotated[FirstItem, Tag("first")], Annotated[OtherItem, Tag("other")]],
        Field(discriminator="value"),
    ]

    @app.post("/items/")
    def save_union_body_discriminator(
        item: Item, q: Annotated[str, Field(description="Query string")]
    ) -> dict[str, Any]:
        return {"item": item}

from inline_snapshot import snapshot
from pydantic import BaseModel


@pytest.fixture(name="client")
def client_fixture() -> TestClient:
    from fastapi import Body
    from pydantic import Discriminator, Tag

    class Cat(BaseModel):
        pet_type: str = "cat"
        meows: int

    class Dog(BaseModel):
        pet_type: str = "dog"
        barks: float

    def get_pet_type(v):