Comment 4 for bug 1724524

Submitter: Zuul
Branch: master

commit f73d6eb1dc928c811231e059f293901405bed1ee
Author: John Garbutt <email address hidden>
Date: Wed Oct 18 11:47:49 2017 +0100

    Add test so we remember why CUSTOM_ prefix added

    While it is tempting as an ironic operator to have CUSTOM_FOO in
    placement, nova flavors and ironic resource class attributes,
    allow that makes for a more complicated mapping between ironic
    resource classes and the resource classes in the general case,
    and could cause confusion when there is a typo of CUSTOM vs CUSTM
    that could get mapped very differently into placement.

    Adding this test so it is clear this is a deliberate choice, and
    git blame will find this git commit message.

    Related-Bug: #1724524

    Change-Id: Ie38baea53e41ca7ba8875fd113cd777810f17db7