Read()-ing a response raises ValueError

[Jamie Lennox]

When you read() from a closed HTTPResponse object it returns a b'' [1]. When you read from a closed BytesIO object you get a ValueError. This is very rarely a problem unless you have something like swiftclient that is reading directly from the urllib3 response and expecting this behaviour.

We should be as compatible as possible and fix it to return a b''.

[1] https://hg.python.org/cpython/file/3.4/Lib/http/client.py#l527

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/360137

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/360137
Committed: https://git.openstack.org/cgit/openstack/requests-mock/commit/?id=fe147914a644cabe11648fb313b990730ae25744
Submitter: Jenkins
Branch: master

commit fe147914a644cabe11648fb313b990730ae25744
Author: Jamie Lennox <email address hidden>
Date: Thu Aug 25 10:34:49 2016 +1000

    Return b'' when reading closed response.

    A HTTPResponse returns a b'' when you read from a closed socket. BytesIO
    raises a ValueError. This only comes to light when you are specifically
    reading past the end of the stream in a chunking scenario like
    swiftclient does.

    Change-Id: I67ed45252deac9472cfb011a5eb89130a3791d6b
    Closes-Bug: #1616690