Responses
A utility library for mocking out the requests Python library.
Note
Responses requires Python 2.7 or newer, and requests >= 2.0
Installing
pip install responses
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 (
stror compiled regular expression) - The full resource URL.
-
match_querystring (
bool) - 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 (
strorBufferedReader) - 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.
-
match (
list) - A list of callbacks to match requests based on request body contents.
Matching Request Parameters
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 URLencoded request bodies and you can supply your own for other formats.
import responses
import requests
@responses.activate
def test_calc_api():
responses.add(
responses.POST,
url='http://calc.com/sum',
body="4",
match=[
responses.urlencoded_params_matcher({"left": "1", "right": "3"})
]
)
requests.post("http://calc.com/sum", data={"left": 1, "right": 3})
Matching JSON encoded data can be done with responses.json_params_matcher(). If your application uses other encodings you can build your own matcher that returns True or False if the request parameters match. Your matcher can expect a request_body parameter to be provided by responses.
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
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_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.
Regex can be used like:
responses.add_passthru(re.compile('https://percy.io/\\w+'))
Viewing/Modifying registered responses
Registered responses are available as a private attribute of the RequestMock instance. It is sometimes useful for debugging purposes to view the stack of registered responses which can be accessed via responses.mock._matches.
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
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
Responses uses Pytest for testing. You can run all tests by:
pytest
And run a single test by:
pytest -k '<test_function_name>'
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