Responses

A utility library for mocking out the requests Python library.

Note

Responses requires Python 2.7 or newer, and requests >= 2.0

Basics

The core of responses comes from registering mock responses:

import responses

@responses.activate
def test_simple():
    responses.add(responses.GET, 'http://twitter.com/api/1/foobar',
                  json={'error': 'not found'}, status=404)

    resp = requests.get('http://twitter.com/api/1/foobar')

    assert resp.json() == {"error": "not found"}

    assert len(responses.calls) == 1
    assert responses.calls[0].request.url == 'http://twitter.com/api/1/foobar'
    assert responses.calls[0].response.text == '{"error": "not found"}'

If you attempt to fetch a url which doesn't hit a match, responses will raise a ConnectionError:

import responses

from requests.exceptions import ConnectionError

@responses.activate
def test_simple():
    with pytest.raises(ConnectionError):
        requests.get('http://twitter.com/api/1/foobar')

Lastly, you can pass an Exception as the body to trigger an error on the request:

import responses

@responses.activate
def test_simple():
    responses.add(responses.GET, 'http://twitter.com/api/1/foobar',
                  body=Exception('...'))
    with pytest.raises(Exception):
        requests.get('http://twitter.com/api/1/foobar')

Response Parameters

Responses are automatically registered via params on add, but can also be passed directly:

import responses

responses.add(
    responses.Response(
        method='GET',
        url='http://example.com',
    ),
)

The following attributes can be passed to a Response mock:

method (str)

The HTTP method (GET, POST, etc).

url (str or compiled regular expression)

The full resource URL.

match_querystring (bool)

Disabled by default. Include the query string when matching requests.

body (str or BufferedReader)

The response body.

json

A python object representing the JSON response body. Automatically configures the appropriate Content-Type.

status (int)

The HTTP status code.

content_type (content_type)

Defaults to text/plain.

headers (dict)

Response headers.

stream (bool)

Disabled by default. Indicates the response should use the streaming API.

Dynamic Responses

You can utilize callbacks to provide dynamic responses. The callback must return a tuple of (status, headers, body).

import json

import responses
import requests

@responses.activate
def test_calc_api():

    def request_callback(request):
        payload = json.loads(request.body)
        resp_body = {'value': sum(payload['numbers'])}
        headers = {'request-id': '728d329e-0e86-11e4-a748-0c84dc037c13'}
        return (200, headers, json.dumps(resp_body))

    responses.add_callback(
        responses.POST, 'http://calc.com/sum',
        callback=request_callback,
        content_type='application/json',
    )

    resp = requests.post(
        'http://calc.com/sum',
        json.dumps({'numbers': [1, 2, 3]}),
        headers={'content-type': 'application/json'},
    )

    assert resp.json() == {'value': 6}

    assert len(responses.calls) == 1
    assert responses.calls[0].request.url == 'http://calc.com/sum'
    assert responses.calls[0].response.text == '{"value": 6}'
    assert (
        responses.calls[0].response.headers['request-id'] ==
        '728d329e-0e86-11e4-a748-0c84dc037c13'
    )

Responses as a context manager

import responses
import requests


def test_my_api():
    with responses.RequestsMock() as rsps:
        rsps.add(responses.GET, 'http://twitter.com/api/1/foobar',
                 body='{}', status=200,
                 content_type='application/json')
        resp = requests.get('http://twitter.com/api/1/foobar')

        assert resp.status_code == 200

    # outside the context manager requests will hit the remote server
    resp = requests.get('http://twitter.com/api/1/foobar')
    resp.status_code == 404

Assertions on declared responses

When used as a context manager, Responses will, by default, raise an assertion error if a url was registered but not accessed. This can be disabled by passing the assert_all_requests_are_fired value:

import responses
import requests


def test_my_api():
    with responses.RequestsMock(assert_all_requests_are_fired=False) as rsps:
        rsps.add(responses.GET, 'http://twitter.com/api/1/foobar',
                 body='{}', status=200,
                 content_type='application/json')

Multiple Responses

You can also add multiple responses for the same url:

import responses
import requests

@responses.activate
def test_my_api():
    responses.add(responses.GET, 'http://twitter.com/api/1/foobar', status=500)
    responses.add(responses.GET, 'http://twitter.com/api/1/foobar',
                  body='{}', status=200,
                  content_type='application/json')

    resp = requests.get('http://twitter.com/api/1/foobar')
    assert resp.status_code == 500
    resp = requests.get('http://twitter.com/api/1/foobar')
    assert resp.status_code == 200

Using a callback to modify the response

If you use customized processing in requests via subclassing/mixins, or if you have library tools that interact with requests at a low level, you may need to add extended processing to the mocked Response object to fully simlulate the environment for your tests. A response_callback can be used, which will be wrapped by the library before being returned to the caller. The callback accepts a response as it's single argument, and is expected to return a single response object.

import responses
import requests

    def response_callback(resp):
            resp.callback_processed = True
            return resp

    with responses.RequestsMock(response_callback=response_callback) as m:
            m.add(responses.GET, 'http://example.com', body=b'test')
            resp = requests.get('http://example.com')
            assert resp.text == "test"
            assert hasattr(resp, 'callback_processed')
            assert resp.callback_processed is True