Responses
=========
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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:
.. code-block:: python
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``:
.. code-block:: python
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:
.. code-block:: python
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:
.. code-block:: python
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``)
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``)
Disabled by default. Indicates the response should use the streaming API.
auto_calculate_content_length (``bool``)
Disabled by default. Automatically calculates the length of a supplied string or JSON body.
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.
.. code-block:: python
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})
Matching JSON encoded data can be done with ``matchers.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`` parameter to be provided by responses.
Similarly, you can use the ``matchers.query_param_matcher`` function to match
against the ``params`` request parameter.
Note, you must set ``match_querystring=False``
.. code-block:: python
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
Dynamic Responses
-----------------
You can utilize callbacks to provide dynamic responses. The callback must return
a tuple of (``status``, ``headers``, ``body``).
.. code-block:: python
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:
.. code-block:: python
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``:
.. code-block:: python
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``:
.. code-block:: python
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
------------------------------
.. code-block:: python
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
-----------------------------
.. code-block:: python
@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
.. code-block:: python
def setUp():
self.responses = responses.RequestsMock()
self.responses.start()
# self.responses.add(...)
self.addCleanup(self.responses.stop)
self.addCleanup(self.responses.reset)
def test_api(self):
self.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:
.. code-block:: python
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.
.. code-block:: python
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:
.. code-block:: python
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.
.. code-block:: python
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:
.. code-block:: python
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:
.. code-block:: python
responses.add_passthru(re.compile('https://percy.io/\\w+'))
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.
.. code-block:: python
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:
.. code-block:: shell
git clone https://github.com/getsentry/responses.git
Create an environment (e.g. with ``virtualenv``):
.. code-block:: shell
virtualenv .env && source .env/bin/activate
Configure development requirements:
.. code-block:: shell
make develop
Responses uses `Pytest <https://docs.pytest.org/en/latest/>`_ for
testing. You can run all tests by:
.. code-block:: shell
pytest
And run a single test by:
.. code-block:: shell
pytest -k '<test_function_name>'
To verify ``type`` compliance, run `mypy <https://github.com/python/mypy>`_ linter:
.. code-block:: shell
mypy --config-file=./mypy.ini -p responses
To check code style and reformat it run:
.. code-block:: shell
pre-commit run --all-files
Note: on some OS, you have to use ``pre_commit``