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 dirty_equals import IsDict
from fastapi.testclient import TestClient


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

        assertEquals(2, testClient.count);
    }

    public void test_doGet_with4Exception_interval100() {
        final FaultTolerantClient client = new FaultTolerantClient();
        client.setRetryInterval(100);
        final TestClient testClient = new TestClient();
        testClient.exceptionCount = 4;
        testClient.interval = 100;

import pytest
from fastapi.testclient import TestClient

from ...utils import needs_py39


@pytest.fixture(name="client")
def get_client():
    from docs_src.dependencies.tutorial008d_an_py39 import app

    client = TestClient(app)
    return client


@needs_py39
def test_get_no_item(client: TestClient):
    response = client.get("/items/foo")
    assert response.status_code == 404, response.text

import pytest
from fastapi.testclient import TestClient

from tests.utils import needs_py39, needs_pydanticv2


@pytest.fixture(name="client")
def get_client():
    from docs_src.request_form_models.tutorial002_an_py39 import app

    client = TestClient(app)
    return client


@needs_pydanticv2
@needs_py39
def test_post_body_form(client: TestClient):

import pytest
from fastapi.testclient import TestClient

from ...utils import needs_py39


@pytest.fixture(name="client")
def get_client():
    from docs_src.dependencies.tutorial008b_an_py39 import app

    client = TestClient(app)
    return client


@needs_py39
def test_get_no_item(client: TestClient):
    response = client.get("/items/foo")
    assert response.status_code == 404, response.text

import pytest
from fastapi.testclient import TestClient

from ...utils import needs_pydanticv2


@pytest.fixture(name="client")
def get_client():
    from docs_src.path_operation_advanced_configuration.tutorial007 import app

    client = TestClient(app)
    return client


@needs_pydanticv2
def test_post(client: TestClient):
    yaml_data = """
        name: Deadpoolio
        tags:
        - x-force
        - x-men

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


@pytest.fixture(name="client")
def get_client():
    from docs_src.request_form_models.tutorial001 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

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 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

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