Mocking cookies with responses - python-requests

Question

I have a piece of code that deals with cookies being set by the server as a response of an HTTP response. I'm attempting to test it using responses, like so:
responses.add(responses.GET, "http://invalid/cookies",
adding_headers = {
"Set-Cookie": "foo=bar; " +
"domain=.invalid; " +
"expires=Fri, 01-Jan-2055 00:00:00 GMT; " +
"path=/; " +
"HttpOnly",
})
I would then expect this to return my cookie, but no such luck.
session = requests.Session()
session.get('http://invalid/cookies')
session.cookies['foo'] # KeyError
Indeed, this works outside of the context of responses.activate:
session = requests.Session()
session.get('https://httpbin.org/cookies/set?foo=bar')
session.cookies['foo'] # 'bar'
How can I mock cookies with responses?

Answer 1

The python3-responses package in Ubuntu 16.04 is out of date. You will need to use a newer version from pip/pip3, after which this behaviour works as expected.
Do note however that this, too, is buggy at the time of writing:
responses.add(responses.GET, 'http://invalid/cookies',
adding_headers = {
"set-cookie": "foo=bar; " +
"domain=.invalid; " +
# "expires=Fri, 01-Jan-2055 00:00:00 GMT; " +
"path=/; " +
"" # "HttpOnly",
})
session = requests.Session()
session.get('http://invalid/cookies')
dict(response.cookies) # this should have one cookie
{'foo': 'bar', 'path': '/', 'domain': '.invalid'}