aioresponses

Aioresponses is a helper to mock/fake web requests in python aiohttp package.

For requests module there are a lot of packages that help us with testing (eg. httpretty, responses, requests-mock).

When it comes to testing asynchronous HTTP requests it is a bit harder (at least at the beginning). The purpose of this package is to provide an easy way to test asynchronous HTTP requests.

Installing

$ pip install aioresponses

Supported versions

• Python 3.7+
• aiohttp>=3.3.0,<4.0.0

Usage

To mock out HTTP request use aioresponses as a method decorator or as a context manager.

Response status code, body, payload (for json response) and headers can be mocked.

Supported HTTP methods: GET, POST, PUT, PATCH, DELETE and OPTIONS.

import aiohttp
import asyncio
from aioresponses import aioresponses

@aioresponses()
def test_request(mocked):
    loop = asyncio.get_event_loop()
    mocked.get('http://example.com', status=200, body='test')
    session = aiohttp.ClientSession()
    resp = loop.run_until_complete(session.get('http://example.com'))

    assert resp.status == 200
    mocked.assert_called_once_with('http://example.com')

for convenience use payload argument to mock out json response. Example below.

as a context manager

import asyncio
import aiohttp
from aioresponses import aioresponses

def test_ctx():
    loop = asyncio.get_event_loop()
    session = aiohttp.ClientSession()
    with aioresponses() as m:
        m.get('http://test.example.com', payload=dict(foo='bar'))

        resp = loop.run_until_complete(session.get('http://test.example.com'))
        data = loop.run_until_complete(resp.json())

        assert dict(foo='bar') == data
        m.assert_called_once_with('http://test.example.com')

aioresponses allows to mock out any HTTP headers

import asyncio
import aiohttp
from aioresponses import aioresponses

@aioresponses()
def test_http_headers(m):
    loop = asyncio.get_event_loop()
    session = aiohttp.ClientSession()
    m.post(
        'http://example.com',
        payload=dict(),
        headers=dict(connection='keep-alive'),
    )

    resp = loop.run_until_complete(session.post('http://example.com'))

    # note that we pass 'connection' but get 'Connection' (capitalized)
    # under the neath `multidict` is used to work with HTTP headers
    assert resp.headers['Connection'] == 'keep-alive'
    m.assert_called_once_with('http://example.com', method='POST')

allows to register different responses for the same url

import asyncio
import aiohttp
from aioresponses import aioresponses

@aioresponses()
def test_multiple_responses(m):
    loop = asyncio.get_event_loop()
    session = aiohttp.ClientSession()
    m.get('http://example.com', status=500)
    m.get('http://example.com', status=200)

    resp1 = loop.run_until_complete(session.get('http://example.com'))
    resp2 = loop.run_until_complete(session.get('http://example.com'))

    assert resp1.status == 500
    assert resp2.status == 200

Repeat response for the same url

E.g. for cases you want to test retrying mechanisms

import asyncio
import aiohttp
from aioresponses import aioresponses

@aioresponses()
def test_multiple_responses(m):
    loop = asyncio.get_event_loop()
    session = aiohttp.ClientSession()
    m.get('http://example.com', status=500, repeat=True)
    m.get('http://example.com', status=200)  # will not take effect

    resp1 = loop.run_until_complete(session.get('http://example.com'))
    resp2 = loop.run_until_complete(session.get('http://example.com'))

    assert resp1.status == 500
    assert resp2.status == 500

match URLs with regular expressions

import asyncio
import aiohttp
import re
from aioresponses import aioresponses

@aioresponses()
def test_regexp_example(m):
    loop = asyncio.get_event_loop()
    session = aiohttp.ClientSession()
    pattern = re.compile(r'^http://example\.com/api\?foo=.*$')
    m.get(pattern, status=200)

    resp = loop.run_until_complete(session.get('http://example.com/api?foo=bar'))

    assert resp.status == 200

allows to make redirects responses

import asyncio
import aiohttp
from aioresponses import aioresponses

@aioresponses()
def test_redirect_example(m):
    loop = asyncio.get_event_loop()
    session = aiohttp.ClientSession()

    # absolute urls are supported
    m.get(
        'http://example.com/',
        headers={'Location': 'http://another.com/'},
        status=307
    )

    resp = loop.run_until_complete(
        session.get('http://example.com/', allow_redirects=True)
    )
    assert resp.url == 'http://another.com/'

    # and also relative
    m.get(
        'http://example.com/',
        headers={'Location': '/test'},
        status=307
    )
    resp = loop.run_until_complete(
        session.get('http://example.com/', allow_redirects=True)
    )
    assert resp.url == 'http://example.com/test'

allows to passthrough to a specified list of servers

import asyncio
import aiohttp
from aioresponses import aioresponses

@aioresponses(passthrough=['http://backend'])
def test_passthrough(m, test_client):
    session = aiohttp.ClientSession()
    # this will actually perform a request
    resp = loop.run_until_complete(session.get('http://backend/api'))

also you can passthrough all requests except specified by mocking object

import asyncio
import aiohttp
from aioresponses import aioresponses

@aioresponses(passthrough_unmatched=True)
def test_passthrough_unmatched(m, test_client):
    url = 'https://httpbin.org/get'
    m.get(url, status=200)
    session = aiohttp.ClientSession()
    # this will actually perform a request
    resp = loop.run_until_complete(session.get('http://backend/api'))
    # this will not perform a request and resp2.status will return 200
    resp2 = loop.run_until_complete(session.get(url))

aioresponses allows to throw an exception

import asyncio
from aiohttp import ClientSession
from aiohttp.http_exceptions import HttpProcessingError
from aioresponses import aioresponses

@aioresponses()
def test_how_to_throw_an_exception(m, test_client):
    loop = asyncio.get_event_loop()
    session = ClientSession()
    m.get('http://example.com/api', exception=HttpProcessingError('test'))

    # calling
    # loop.run_until_complete(session.get('http://example.com/api'))
    # will throw an exception.

aioresponses allows to use callbacks to provide dynamic responses

import asyncio
import aiohttp
from aioresponses import CallbackResult, aioresponses

def callback(url, **kwargs):
    return CallbackResult(status=418)

@aioresponses()
def test_callback(m, test_client):
    loop = asyncio.get_event_loop()
    session = ClientSession()
    m.get('http://example.com', callback=callback)

    resp = loop.run_until_complete(session.get('http://example.com'))

    assert resp.status == 418

aioresponses can be used in a pytest fixture

import pytest
from aioresponses import aioresponses

@pytest.fixture
def mock_aioresponse():
    with aioresponses() as m:
        yield m

Features

• Easy to mock out HTTP requests made by aiohttp.ClientSession

License

• Free software: MIT license

Credits

This package was created with Cookiecutter and the audreyr/cookiecutter-pypackage project template.