responses 0.20.0

A utility library for mocking out the `requests` Python library.

A utility library for mocking out the requests Python library.

Note

Responses requires Python 3.7 or newer, and requests >= 2.0

Table of Contents

Contents

• Table of Contents
• Installing
• Deprecations and Migration Path
• Basics
• Response Parameters
• Matching Requests
  • Matching Request Body Contents
    • URL-encoded data
    • JSON encoded data
  • Query Parameters Matcher
    • Query Parameters as a Dictionary
    • Query Parameters as a String
  • Request Keyword Arguments Matcher
  • Request multipart/form-data Data Validation
  • Request Fragment Identifier Validation
  • Request Headers Validation
  • Creating Custom Matcher
• Response Registry
  • Default Registry
  • Ordered Registry
  • Custom Registry
• Dynamic Responses
• Responses as a context manager
• Responses as a pytest fixture
• Responses inside a unittest setUp()
• Assertions on declared responses
• Assert Request Call Count
• Multiple Responses
• Using a callback to modify the response
• Passing through real requests
• Viewing/Modifying registered responses
• Contributing
  • Environment Configuration
  • Tests and Code Quality Validation
    • Unit tests
    • Type Validation
    • Code Quality and Style

Installing

pip install responses

Deprecations and Migration Path

Here you will find a list of deprecated functionality and a migration path for each. Please ensure to update your code according to the guidance.

Deprecation and Migration

Deprecated Functionality	Deprecated in Version	Migration Path
responses.json_params_matcher	0.14.0	responses.matchers.json_params_matcher
responses.urlencoded_params_matcher	0.14.0	responses.matchers.urlencoded_params_matcher
stream argument in Response and CallbackResponse	0.15.0	Use stream argument in request directly.
match_querystring argument in Response and CallbackResponse.	0.17.0	Use responses.matchers.query_param_matcher or responses.matchers.query_string_matcher
responses.assert_all_requests_are_fired, responses.passthru_prefixes, responses.target	0.20.0	Use responses.mock.assert_all_requests_are_fired, responses.mock.passthru_prefixes, responses.mock.target instead.

Basics

The core of responses comes from registering mock responses:

import responses
import requests

@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
import requests

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
import requests

@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)

DEPRECATED: Use responses.matchers.query_param_matcher or responses.matchers.query_string_matcher

Include the query string when matching requests. Enabled by default if the response URL contains a query string, disabled if it doesn’t or the URL is a regular expression.

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)

DEPRECATED: use stream argument in request directly

auto_calculate_content_length (bool)

Disabled by default. Automatically calculates the length of a supplied string or JSON body.

match (tuple)

An iterable (tuple is recommended) of callbacks to match requests based on request attributes. Current module provides multiple matchers that you can use to match:

• body contents in JSON format
• body contents in URL encoded data format
• request query parameters
• request query string (similar to query parameters but takes string as input)
• kwargs provided to request e.g. stream, verify
• ‘multipart/form-data’ content and headers in request
• request headers
• request fragment identifier

Alternatively user can create custom matcher. Read more Matching Requests

Matching Requests

Matching Request Body Contents

When adding responses for endpoints that are sent request data you can add matchers to ensure your code is sending the right parameters and provide different responses based on the request body contents. responses provides matchers for JSON and URL-encoded request bodies.

URL-encoded data

import responses
import requests
from responses import matchers

@responses.activate
def test_calc_api():
    responses.add(
        responses.POST,
        url='http://calc.com/sum',
        body="4",
        match=[
            matchers.urlencoded_params_matcher({"left": "1", "right": "3"})
        ]
    )
    requests.post("http://calc.com/sum", data={"left": 1, "right": 3})

JSON encoded data

Matching JSON encoded data can be done with matchers.json_params_matcher().

import responses
import requests
from responses import matchers

@responses.activate
def test_calc_api():
    responses.add(
        method=responses.POST,
        url="http://example.com/",
        body="one",
        match=[matchers.json_params_matcher({"page": {"name": "first", "type": "json"}})],
    )
    resp = requests.request(
        "POST",
        "http://example.com/",
        headers={"Content-Type": "application/json"},
        json={"page": {"name": "first", "type": "json"}},
    )

Query Parameters Matcher

Query Parameters as a Dictionary

You can use the matchers.query_param_matcher function to match against the params request parameter. Just use the same dictionary as you will use in params argument in request.

Note, do not use query parameters as part of the URL. Avoid using match_querystring deprecated argument.

import responses
import requests
from responses import matchers

@responses.activate
def test_calc_api():
    url = "http://example.com/test"
    params = {"hello": "world", "I am": "a big test"}
    responses.add(
        method=responses.GET,
        url=url,
        body="test",
        match=[matchers.query_param_matcher(params)],
        match_querystring=False,
    )

    resp = requests.get(url, params=params)

    constructed_url = r"http://example.com/test?I+am=a+big+test&hello=world"
    assert resp.url == constructed_url
    assert resp.request.url == constructed_url
    assert resp.request.params == params

By default, matcher will validate that all parameters match strictly. To validate that only parameters specified in the matcher are present in original request use strict_match=False.

Query Parameters as a String

As alternative, you can use query string value in matchers.query_string_matcher to match query parameters in your request

import requests
import responses
from responses import matchers

@responses.activate
def my_func():
    responses.add(
        responses.GET,
        "https://httpbin.org/get",
        match=[matchers.query_string_matcher("didi=pro&test=1")],
    )
    resp = requests.get("https://httpbin.org/get", params={"test": 1, "didi": "pro"})

my_func()

Request Keyword Arguments Matcher

To validate request arguments use the matchers.request_kwargs_matcher function to match against the request kwargs.

Note, only arguments provided to matchers.request_kwargs_matcher will be validated.

import responses
import requests
from responses import matchers

with responses.RequestsMock(assert_all_requests_are_fired=False) as rsps:
    req_kwargs = {
        "stream": True,
        "verify": False,
    }
    rsps.add(
        "GET",
        "http://111.com",
        match=[matchers.request_kwargs_matcher(req_kwargs)],
    )

    requests.get("http://111.com", stream=True)

    # >>>  Arguments don't match: {stream: True, verify: True} doesn't match {stream: True, verify: False}

Request multipart/form-data Data Validation

To validate request body and headers for multipart/form-data data you can use matchers.multipart_matcher. The data, and files parameters provided will be compared to the request:

import requests
import responses
from responses.matchers import multipart_matcher

@responses.activate
def my_func():
    req_data = {"some": "other", "data": "fields"}
    req_files = {"file_name": b"Old World!"}
    responses.add(
        responses.POST, url="http://httpbin.org/post",
        match=[multipart_matcher(req_files, data=req_data)]
    )
    resp = requests.post("http://httpbin.org/post", files={"file_name": b"New World!"})

my_func()
# >>> raises ConnectionError: multipart/form-data doesn't match. Request body differs.

Request Fragment Identifier Validation

To validate request URL fragment identifier you can use matchers.fragment_identifier_matcher. The matcher takes fragment string (everything after # sign) as input for comparison:

import requests
import responses
from responses.matchers import fragment_identifier_matcher

@responses.activate
def run():
    url = "http://example.com?ab=xy&zed=qwe#test=1&foo=bar"
    responses.add(
        responses.GET,
        url,
        match_querystring=True,
        match=[fragment_identifier_matcher("test=1&foo=bar")],
        body=b"test",
    )

    # two requests to check reversed order of fragment identifier
    resp = requests.get("http://example.com?ab=xy&zed=qwe#test=1&foo=bar")
    resp = requests.get("http://example.com?zed=qwe&ab=xy#foo=bar&test=1")

run()

Request Headers Validation

When adding responses you can specify matchers to ensure that your code is sending the right headers and provide different responses based on the request headers.

import responses
import requests
from responses import matchers


@responses.activate
def test_content_type():
    responses.add(
        responses.GET,
        url="http://example.com/",
        body="hello world",
        match=[
            matchers.header_matcher({"Accept": "text/plain"})
        ]
    )

    responses.add(
        responses.GET,
        url="http://example.com/",
        json={"content": "hello world"},
        match=[
            matchers.header_matcher({"Accept": "application/json"})
        ]
    )

    # request in reverse order to how they were added!
    resp = requests.get("http://example.com/", headers={"Accept": "application/json"})
    assert resp.json() == {"content": "hello world"}

    resp = requests.get("http://example.com/", headers={"Accept": "text/plain"})
    assert resp.text == "hello world"

Because requests will send several standard headers in addition to what was specified by your code, request headers that are additional to the ones passed to the matcher are ignored by default. You can change this behaviour by passing strict_match=True to the matcher to ensure that only the headers that you’re expecting are sent and no others. Note that you will probably have to use a PreparedRequest in your code to ensure that requests doesn’t include any additional headers.

import responses
import requests
from responses import matchers

@responses.activate
def test_content_type():
    responses.add(
        responses.GET,
        url="http://example.com/",
        body="hello world",
        match=[
            matchers.header_matcher({"Accept": "text/plain"}, strict_match=True)
        ]
    )

    # this will fail because requests adds its own headers
    with pytest.raises(ConnectionError):
        requests.get("http://example.com/", headers={"Accept": "text/plain"})

    # a prepared request where you overwrite the headers before sending will work
    session = requests.Session()
    prepped = session.prepare_request(
        requests.Request(
            method="GET",
            url="http://example.com/",
        )
    )
    prepped.headers = {"Accept": "text/plain"}

    resp = session.send(prepped)
    assert resp.text == "hello world"

Creating Custom Matcher

If your application requires other encodings or different data validation you can build your own matcher that returns Tuple[matches: bool, reason: str]. Where boolean represents True or False if the request parameters match and the string is a reason in case of match failure. Your matcher can expect a PreparedRequest parameter to be provided by responses.

Note, PreparedRequest is customized and has additional attributes params and req_kwargs.

Response Registry

Default Registry

By default, responses will search all registered Response objects and return a match. If only one Response is registered, the registry is kept unchanged. However, if multiple matches are found for the same request, then first match is returned and removed from registry.

Ordered Registry

In some scenarios it is important to preserve the order of the requests and responses. You can use registries.OrderedRegistry to force all Response objects to be dependent on the insertion order and invocation index. In following example we add multiple Response objects that target the same URL. However, you can see, that status code will depend on the invocation order.

@responses.activate(registry=OrderedRegistry)
def test_invocation_index():
    responses.add(
        responses.GET,
        "http://twitter.com/api/1/foobar",
        json={"msg": "not found"},
        status=404,
    )
    responses.add(
        responses.GET,
        "http://twitter.com/api/1/foobar",
        json={"msg": "OK"},
        status=200,
    )
    responses.add(
        responses.GET,
        "http://twitter.com/api/1/foobar",
        json={"msg": "OK"},
        status=200,
    )
    responses.add(
        responses.GET,
        "http://twitter.com/api/1/foobar",
        json={"msg": "not found"},
        status=404,
    )

    resp = requests.get("http://twitter.com/api/1/foobar")
    assert resp.status_code == 404
    resp = requests.get("http://twitter.com/api/1/foobar")
    assert resp.status_code == 200
    resp = requests.get("http://twitter.com/api/1/foobar")
    assert resp.status_code == 200
    resp = requests.get("http://twitter.com/api/1/foobar")
    assert resp.status_code == 404

Custom Registry

Built-in registries are suitable for most of use cases, but to handle special conditions, you can implement custom registry which must follow interface of registries.FirstMatchRegistry. Redefining the find method will allow you to create custom search logic and return appropriate Response

Example that shows how to set custom registry

import responses
from responses import registries


class CustomRegistry(registries.FirstMatchRegistry):
    pass


print("Before tests:", responses.mock.get_registry())
""" Before tests: <responses.registries.FirstMatchRegistry object> """

# using function decorator
@responses.activate(registry=CustomRegistry)
def run():
    print("Within test:", responses.mock.get_registry())
    """ Within test: <__main__.CustomRegistry object> """

run()

print("After test:", responses.mock.get_registry())
""" After test: <responses.registries.FirstMatchRegistry object> """

# using context manager
with responses.RequestsMock(registry=CustomRegistry) as rsps:
    print("In context manager:", rsps.get_registry())
    """ In context manager: <__main__.CustomRegistry object> """

print("After exit from context manager:", responses.mock.get_registry())
"""
After exit from context manager: <responses.registries.FirstMatchRegistry object>
"""

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'
    )

You can also pass a compiled regex to add_callback to match multiple urls:

import re, json

from functools import reduce

import responses
import requests

operators = {
  'sum': lambda x, y: x+y,
  'prod': lambda x, y: x*y,
  'pow': lambda x, y: x**y
}

@responses.activate
def test_regex_url():

    def request_callback(request):
        payload = json.loads(request.body)
        operator_name = request.path_url[1:]

        operator = operators[operator_name]

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

    responses.add_callback(
        responses.POST,
        re.compile('http://calc.com/(sum|prod|pow|unsupported)'),
        callback=request_callback,
        content_type='application/json',
    )

    resp = requests.post(
        'http://calc.com/prod',
        json.dumps({'numbers': [2, 3, 4]}),
        headers={'content-type': 'application/json'},
    )
    assert resp.json() == {'value': 24}

test_regex_url()

If you want to pass extra keyword arguments to the callback function, for example when reusing a callback function to give a slightly different result, you can use functools.partial:

from functools import partial

...

    def request_callback(request, id=None):
        payload = json.loads(request.body)
        resp_body = {'value': sum(payload['numbers'])}
        headers = {'request-id': id}
        return (200, headers, json.dumps(resp_body))

    responses.add_callback(
        responses.POST, 'http://calc.com/sum',
        callback=partial(request_callback, id='728d329e-0e86-11e4-a748-0c84dc037c13'),
        content_type='application/json',
    )

You can see params passed in the original request in responses.calls[].request.params:

import responses
import requests

@responses.activate
def test_request_params():
    responses.add(
        method=responses.GET,
        url="http://example.com?hello=world",
        body="test",
        match_querystring=False,
    )

    resp = requests.get('http://example.com', params={"hello": "world"})
    assert responses.calls[0].request.params == {"hello": "world"}

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

Responses as a pytest fixture

@pytest.fixture
def mocked_responses():
    with responses.RequestsMock() as rsps:
        yield rsps

def test_api(mocked_responses):
    mocked_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 == 200

Responses inside a unittest setUp()

When run with unittest tests, this can be used to set up some generic class-level responses, that may be complemented by each test

class TestMyApi(unittest.TestCase):
    def setUp(self):
        responses.add(responses.GET, 'https://example.com', body="within setup")
        # here go other self.responses.add(...)

    @responses.activate
    def test_my_func(self):
        responses.add(
            responses.GET,
            "https://httpbin.org/get",
            match=[matchers.query_param_matcher({"test": "1", "didi": "pro"})],
            body="within test"
        )
        resp = requests.get("https://example.com")
        resp2 = requests.get("https://httpbin.org/get", params={"test": "1", "didi": "pro"})
        print(resp.text)
        # >>> within setup
        print(resp2.text)
        # >>> within test

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')

Assert Request Call Count

Assert that the request was called exactly n times.

import responses
import requests

@responses.activate
def test_assert_call_count():
    responses.add(responses.GET, "http://example.com")

    requests.get("http://example.com")
    assert responses.assert_call_count("http://example.com", 1) is True

    requests.get("http://example.com")
    with pytest.raises(AssertionError) as excinfo:
        responses.assert_call_count("http://example.com", 1)
    assert "Expected URL 'http://example.com' to be called 1 times. Called 2 times." in str(excinfo.value)

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 simulate 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

Passing through real requests

In some cases you may wish to allow for certain requests to pass through responses and hit a real server. This can be done with the add_passthru methods:

import responses

@responses.activate
def test_my_api():
    responses.add_passthru('https://percy.io')

This will allow any requests matching that prefix, that is otherwise not registered as a mock response, to passthru using the standard behavior.

Pass through endpoints can be configured with regex patterns if you need to allow an entire domain or path subtree to send requests:

responses.add_passthru(re.compile('https://percy.io/\\w+'))

Lastly, you can use the response.passthrough attribute on BaseResponse or use PassthroughResponse to enable a response to behave as a pass through.

# Enable passthrough for a single response
response = Response(responses.GET, 'http://example.com', body='not used')
response.passthrough = True
responses.add(response)

# Use PassthroughResponse
response = PassthroughResponse(responses.GET, 'http://example.com')
responses.add(response)

Viewing/Modifying registered responses

Registered responses are available as a public method of the RequestMock instance. It is sometimes useful for debugging purposes to view the stack of registered responses which can be accessed via responses.registered().

The replace function allows a previously registered response to be changed. The method signature is identical to add. response s are identified using method and url. Only the first matched response is replaced.

import responses
import requests

@responses.activate
def test_replace():

    responses.add(responses.GET, 'http://example.org', json={'data': 1})
    responses.replace(responses.GET, 'http://example.org', json={'data': 2})

    resp = requests.get('http://example.org')

    assert resp.json() == {'data': 2}

The upsert function allows a previously registered response to be changed like replace. If the response is registered, the upsert function will registered it like add.

remove takes a method and url argument and will remove all matched responses from the registered list.

Finally, reset will reset all registered responses.

Contributing

Environment Configuration

Responses uses several linting and autoformatting utilities, so it’s important that when submitting patches you use the appropriate toolchain:

Clone the repository:

git clone https://github.com/getsentry/responses.git

Create an environment (e.g. with virtualenv):

virtualenv .env && source .env/bin/activate

Configure development requirements:

make develop

Tests and Code Quality Validation

The easiest way to validate your code is to run tests via tox. Current tox configuration runs the same checks that are used in GitHub Actions CI/CD pipeline.

Please execute the following command line from the project root to validate your code against:

• Unit tests in all Python versions that are supported by this project
• Type validation via mypy
• All pre-commit hooks

tox

Alternatively, you can always run a single test. See documentation below.

Unit tests

Responses uses Pytest for testing. You can run all tests by:

tox -e py37
tox -e py310

OR manually activate required version of Python and run

pytest

And run a single test by:

pytest -k '<test_function_name>'

Type Validation

To verify type compliance, run mypy linter:

tox -e mypy

OR

mypy --config-file=./mypy.ini -p responses

Code Quality and Style

To check code style and reformat it run:

tox -e precom

OR

pre-commit run --all-files