!!! info
    To use `TestClient`, first install <a href="https://www.python-httpx.org" class="external-link" target="_blank">`httpx`</a>.

    E.g. `pip install httpx`.

Import `TestClient`.

Create a `TestClient` by passing your **FastAPI** application to it.

Create functions with a name that starts with `test_` (this is standard `pytest` conventions).

Use the `TestClient` object the same way as you do with `httpx`.

### <a href="https://webargs.readthedocs.io/en/latest/" class="external-link" target="_blank">Webargs</a>

Another big feature required by APIs is <abbr title="reading and converting to Python data">parsing</abbr> data from incoming requests.

Webargs is a tool that was made to provide that on top of several frameworks, including Flask.

    assert response.status_code == 422
    assert response.json() == IsDict(
        {
            "detail": [
                {
                    "type": "float_parsing",
                    "loc": ["body", "price"],
                    "msg": "Input should be a valid number, unable to parse string as a number",
                    "input": "twenty",
                }
            ]

    assert response.status_code == 422
    assert response.json() == IsDict(
        {
            "detail": [
                {
                    "type": "float_parsing",
                    "loc": ["body", "price"],
                    "msg": "Input should be a valid number, unable to parse string as a number",
                    "input": "twenty",
                }
            ]

        str,
        Doc(
            """
            The media type of this parameter field. Changing it would affect the
            generated OpenAPI, but currently it doesn't affect the parsing of the data.
            """
        ),
    ] = "application/json",
    alias: Annotated[
        Optional[str],
        Doc(
            """

            Doc(
                """
                The OAuth2 spec says it is required and MUST be the fixed string
                "password". Nevertheless, this dependency class is permissive and
                allows not passing it. If you want to enforce it, use instead the
                `OAuth2PasswordRequestFormStrict` dependency.
                """
            ),
        ] = None,
        username: Annotated[
            str,

### Always `raise` in Dependencies with `yield` and `except`

If you catch an exception in a dependency with `yield`, unless you are raising another `HTTPException` or similar, you should re-raise the original exception.

    def __str__(self):
        return self.uuid

    @property  # type: ignore
    def __class__(self):
        return uuid.UUID

    @property
    def __dict__(self):
        """Spoof a missing __dict__ by raising TypeError, this is how
        asyncpg.pgroto.pgproto.UUID behaves"""
        raise TypeError("vars() argument must have __dict__ attribute")


@needs_pydanticv2
def test_pydanticv2():

## 0.110.0

### Breaking Changes

* 🐛 Fix unhandled growing memory for internal server errors, refactor dependencies with `yield` and `except` to require raising again as in regular Python. PR [#11191](https://github.com/tiangolo/fastapi/pull/11191) by [@tiangolo](https://github.com/tiangolo).

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