requests-mock-flask 2026.4.2

Helpers to use requests_mock and responses with a Flask test client.

requests-mock-flask

requests-mock-flask helps with testing Flask applications with httpretty, respx, responses or requests-mock.

• Installation

• Usage examples

• Use cases

• Full documentation

Installation

Requires Python 3.12+.

pip install requests-mock-flask

Usage examples

"""Examples of using requests-mock-flask."""

from http import HTTPStatus

import flask
import httpretty  # pyright: ignore[reportMissingTypeStubs]
import httpx
import requests
import requests_mock
import responses
import respx

from requests_mock_flask import add_flask_app_to_mock

app = flask.Flask(import_name="example_app")


@app.route(rule="/")
def _() -> str:
    """Return a simple message."""
    return "Hello, World!"


# Using responses
with responses.RequestsMock(assert_all_requests_are_fired=False) as resp_m:
    add_flask_app_to_mock(
        mock_obj=resp_m,
        flask_app=app,
        base_url="http://www.example.com",
    )

    response = requests.get(url="http://www.example.com", timeout=30)

assert response.status_code == HTTPStatus.OK
assert response.text == "Hello, World!"


# Using requests-mock
with requests_mock.Mocker() as req_m:
    add_flask_app_to_mock(
        mock_obj=req_m,
        flask_app=app,
        base_url="http://www.example.com",
    )

    response = requests.get(url="http://www.example.com", timeout=30)

assert response.status_code == HTTPStatus.OK
assert response.text == "Hello, World!"


# Using a requests-mock adapter
session = requests.Session()
adapter = requests_mock.Adapter()
session.mount(prefix="mock", adapter=adapter)

add_flask_app_to_mock(
    mock_obj=adapter,
    flask_app=app,
    base_url="mock://www.example.com",
)

response = session.get(url="mock://www.example.com", timeout=30)

assert response.status_code == HTTPStatus.OK
assert response.text == "Hello, World!"


# Using httpretty
with httpretty.core.httprettized():  # type: ignore[no-untyped-call]
    add_flask_app_to_mock(
        mock_obj=httpretty,
        flask_app=app,
        base_url="http://www.example.com",
    )

    response = requests.get(url="http://www.example.com", timeout=30)

assert response.status_code == HTTPStatus.OK
assert response.text == "Hello, World!"


# Using respx
with respx.mock(assert_all_called=False) as respx_mock:
    add_flask_app_to_mock(
        mock_obj=respx_mock,
        flask_app=app,
        base_url="http://www.example.com",
    )

    httpx_response = httpx.get(url="http://www.example.com")

assert httpx_response.status_code == HTTPStatus.OK
assert httpx_response.text == "Hello, World!"

Use cases

• Use requests or other Python APIs for testing Flask applications.

• Create a test suite which can test a Flask application as well as a live web application, to make a verified fake.

• Test a service which calls a Flask application that you have the source code for.

Full documentation

See the full documentation for more information including how to contribute.