("traceparent", "123"),
            ("x_tag", "one"),
            ("x_tag", "two"),
        ],
    )
    assert response.status_code == 200
    assert response.json() == {
        "host": "testserver",
        "save_data": True,
        "if_modified_since": "yesterday",
        "traceparent": "123",
        "x_tag": ["one", "two"],
    }

    )
    assert response.status_code == 200
    assert response.json() == {
        "host": "testserver",
        "save_data": True,
        "if_modified_since": "yesterday",
        "traceparent": "123",
        "x_tag": ["one", "two"],
    }


def test_header_param_model_defaults(client: TestClient):
    response = client.get("/items/", headers=[("save-data", "true")])
    assert response.status_code == 200

    assert response.json() == {
        "host": "testserver",
        "save_data": True,
        "if_modified_since": "yesterday",
        "traceparent": "123",
        "x_tag": ["one", "two"],
    }


def test_header_param_model_defaults(client: TestClient):
    response = client.get("/items/", headers=[("save-data", "true")])
    assert response.status_code == 200

from pydantic import BaseModel

app = FastAPI()


class CommonHeaders(BaseModel):
    host: str
    save_data: bool
    if_modified_since: str | None = None
    traceparent: str | None = None
    x_tag: list[str] = []


@app.get("/items/")
async def read_items(headers: CommonHeaders = Header()):

from pydantic import BaseModel

app = FastAPI()


class CommonHeaders(BaseModel):
    host: str
    save_data: bool
    if_modified_since: Union[str, None] = None
    traceparent: Union[str, None] = None
    x_tag: list[str] = []


@app.get("/items/")
async def read_items(headers: CommonHeaders = Header(convert_underscores=False)):

from pydantic import BaseModel

app = FastAPI()


class CommonHeaders(BaseModel):
    host: str
    save_data: bool
    if_modified_since: Union[str, None] = None
    traceparent: Union[str, None] = None
    x_tag: list[str] = []


@app.get("/items/")
async def read_items(
    headers: Annotated[CommonHeaders, Header(convert_underscores=False)],
):

from pydantic import BaseModel

app = FastAPI()


class CommonHeaders(BaseModel):
    host: str
    save_data: bool
    if_modified_since: str | None = None
    traceparent: str | None = None
    x_tag: list[str] = []


@app.get("/items/")
async def read_items(headers: Annotated[CommonHeaders, Header()]):

from pydantic import BaseModel

app = FastAPI()


class CommonHeaders(BaseModel):
    host: str
    save_data: bool
    if_modified_since: Union[str, None] = None
    traceparent: Union[str, None] = None
    x_tag: list[str] = []


@app.get("/items/")
async def read_items(headers: CommonHeaders = Header()):

from pydantic import BaseModel

app = FastAPI()


class CommonHeaders(BaseModel):
    host: str
    save_data: bool
    if_modified_since: str | None = None
    traceparent: str | None = None
    x_tag: list[str] = []


@app.get("/items/")
async def read_items(headers: CommonHeaders = Header(convert_underscores=False)):

from pydantic import BaseModel

app = FastAPI()


class CommonHeaders(BaseModel):
    host: str
    save_data: bool
    if_modified_since: str | None = None
    traceparent: str | None = None
    x_tag: list[str] = []


@app.get("/items/")
async def read_items(
    headers: Annotated[CommonHeaders, Header(convert_underscores=False)],
):