# Testclient – `TestClient`

Sie können die `TestClient`-Klasse verwenden, um FastAPI-Anwendungen zu testen, ohne eine tatsächliche HTTP- und Socket-Verbindung zu erstellen, Sie kommunizieren einfach direkt mit dem FastAPI-Code.

Lesen Sie mehr darüber in der [FastAPI-Dokumentation über Testen](../tutorial/testing.md).

Sie können sie direkt von `fastapi.testclient` importieren:

```python
from fastapi.testclient import TestClient
```

You can use the `TestClient` class to test FastAPI applications without creating an actual HTTP and socket connection, just communicating directly with the FastAPI code.

Read more about it in the [FastAPI docs for Testing](https://fastapi.tiangolo.com/tutorial/testing/).

You can import it directly from `fastapi.testclient`:

```python
from fastapi.testclient import TestClient
```

import pytest
from fastapi.testclient import TestClient


@pytest.fixture(name="client")
def get_client():
    from docs_src.dependencies.tutorial008d_an import app

    client = TestClient(app)
    return client


def test_get_no_item(client: TestClient):
    response = client.get("/items/foo")
    assert response.status_code == 404, response.text
    assert response.json() == {"detail": "Item not found, there's only a plumbus here"}

import pytest
from dirty_equals import IsDict
from fastapi.testclient import TestClient


@pytest.fixture(name="client")
def get_client():
    from docs_src.bigger_applications.app_an.main import app

    client = TestClient(app)
    return client


def test_users_token_jessica(client: TestClient):
    response = client.get("/users?token=jessica")
    assert response.status_code == 200

import pytest
from dirty_equals import IsDict
from fastapi.testclient import TestClient

from ...utils import needs_py39


@pytest.fixture(name="client")
def get_client():
    from docs_src.bigger_applications.app_an_py39.main import app

    client = TestClient(app)
    return client


@needs_py39
def test_users_token_jessica(client: TestClient):
    response = client.get("/users?token=jessica")

from unittest.mock import patch

import pytest
from dirty_equals import IsDict
from fastapi.testclient import TestClient


@pytest.fixture
def client():
    from docs_src.body.tutorial001 import app

    client = TestClient(app)
    return client


def test_body_float(client: TestClient):
    response = client.post("/items/", json={"name": "Foo", "price": 50.5})
    assert response.status_code == 200

from unittest.mock import patch

import pytest
from dirty_equals import IsDict
from fastapi.testclient import TestClient

from ...utils import needs_py310


@pytest.fixture
def client():
    from docs_src.body.tutorial001_py310 import app

    client = TestClient(app)
    return client


@needs_py310
def test_body_float(client: TestClient):
    response = client.post("/items/", json={"name": "Foo", "price": 50.5})

import pytest
from dirty_equals import IsDict
from fastapi.testclient import TestClient


@pytest.fixture(name="client")
def get_client():
    from docs_src.query_params_str_validations.tutorial010_an import app

    client = TestClient(app)
    return client


def test_query_params_str_validations_no_query(client: TestClient):
    response = client.get("/items/")
    assert response.status_code == 200

import pytest
from dirty_equals import IsDict
from fastapi.testclient import TestClient


@pytest.fixture(name="client")
def get_client():
    from docs_src.request_forms.tutorial001_an import app

    client = TestClient(app)
    return client


def test_post_body_form(client: TestClient):
    response = client.post("/login/", data={"username": "Foo", "password": "secret"})
    assert response.status_code == 200

## Using `TestClient`

!!! 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).