Comment 7 for bug 1879578

Reviewed: https://review.opendev.org/740598
Committed: https://git.openstack.org/cgit/openstack/cinder/commit/?id=5122b146589368189ae1645985cc10030c90ecc5
Submitter: Zuul
Branch: stable/train

commit 5122b146589368189ae1645985cc10030c90ecc5
Author: Brian Rosmaita <email address hidden>
Date: Wed May 20 16:15:26 2020 -0400

    Default volume_type set too early

    If a volume_type is not specified in a volume-create request, change
    I4da0c13b5b3f8174a30b8557f968d6b9e641b091 (introduced in Train) sets a
    default volume_type in the REST API layer. This prevents the
    selection logic in cinder.volume.flows.api.create_volume.
    ExtractVolumeRequestTask from being able to infer the appropriate
    volume_type from the source volume, snapshot, or image metadata, and
    has caused a regression where the created volume is of the default
    type instead of the inferred type.

    This patch removes setting the default volume_type in the REST API
    and modifies the selection code in ExtractVolumeRequestTask slightly
    to make sure a volume_type is always assigned in that function, and
    adds and revises some tests.

    Change-Id: I05915f2e32b1229ad320cd1c5748de3d63183b91
    Closes-bug: #1879578
    (cherry picked from commit 674c8e7286999bb6408291de1dc6395aac2b04b1)
    Conflicts:
      cinder/tests/unit/volume/flows/api/test_create_volume.py
      - cinder.tests.unit.test (victoria) -> cinder.test (pre-victoria)
    (cherry picked from commit c1bdb233cfd5b32a8b60b481e67abc9b4613893c)
    Conflicts:
      cinder/volume/flows/api/create_volume.py
      - add six, remove collections
      cinder/tests/unit/volume/flows/api/test_create_volume.py
      - add mock, remove unittest.mock