@pytest.mark.parametrize(
    "path,headers,expected_status,expected_response",
    [
        ("/items", None, 200, {"X-Token values": None}),
        ("/items", {"x-token": "foo"}, 200, {"X-Token values": ["foo"]}),
        # TODO: fix this, is it a bug?
        # ("/items", [("x-token", "foo"), ("x-token", "bar")], 200, {"X-Token values": ["foo", "bar"]}),
    ],
)
def test(path, headers, expected_status, expected_response, client: TestClient):

@pytest.mark.parametrize(
    "path,headers,expected_status,expected_response",
    [
        ("/items", None, 200, {"X-Token values": None}),
        ("/items", {"x-token": "foo"}, 200, {"X-Token values": ["foo"]}),
        # TODO: fix this, is it a bug?
        # ("/items", [("x-token", "foo"), ("x-token", "bar")], 200, {"X-Token values": ["foo", "bar"]}),
    ],
)
def test(path, headers, expected_status, expected_response, client: TestClient):

    !!! tip
        Prefer to use the `Annotated` version if possible.

    ```Python hl_lines="8  13"
    {!> ../../../docs_src/dependencies/tutorial006.py!}
    ```

### Return values

And they can return values or not, the values won't be used.

So, you can re-use a normal dependency (that returns a value) you already use somewhere else, and even though the value won't be used, the dependency will be executed:

* Data validation
* Automatic documentation

## Defaults

As query parameters are not a fixed part of a path, they can be optional and can have default values.

In the example above they have default values of `skip=0` and `limit=10`.

So, going to the URL:

```
http://127.0.0.1:8000/items/
```

would be the same as going to:

```
http://127.0.0.1:8000/items/?skip=0&limit=10

from docs_src.query_params_str_validations.tutorial013 import app

client = TestClient(app)


def test_multi_query_values():
    url = "/items/?q=foo&q=bar"
    response = client.get(url)
    assert response.status_code == 200, response.text
    assert response.json() == {"q": ["foo", "bar"]}


def test_query_no_values():
    url = "/items/"
    response = client.get(url)
    assert response.status_code == 200, response.text

It doesn't return a large `str` containing the data in JSON format (as a string). It returns a Python standard data structure (e.g. a `dict`) with values and sub-values that are all compatible with JSON.

!!! note

from docs_src.query_params_str_validations.tutorial011 import app

client = TestClient(app)


def test_multi_query_values():
    url = "/items/?q=foo&q=bar"
    response = client.get(url)
    assert response.status_code == 200, response.text
    assert response.json() == {"q": ["foo", "bar"]}


def test_query_no_values():
    url = "/items/"
    response = client.get(url)
    assert response.status_code == 200, response.text

from docs_src.query_params_str_validations.tutorial011_an import app

client = TestClient(app)


def test_multi_query_values():
    url = "/items/?q=foo&q=bar"
    response = client.get(url)
    assert response.status_code == 200, response.text
    assert response.json() == {"q": ["foo", "bar"]}


def test_query_no_values():
    url = "/items/"
    response = client.get(url)
    assert response.status_code == 200, response.text

from typing import Annotated

from fastapi import FastAPI, Header

app = FastAPI()


@app.get("/items/")
async def read_items(x_token: Annotated[list[str] | None, Header()] = None):

## Query parameter list / multiple values

When you define a query parameter explicitly with `Query` you can also declare it to receive a list of values, or said in other way, to receive multiple values.

For example, to declare a query parameter `q` that can appear multiple times in the URL, you can write:

=== "Python 3.10+"