Failing BuildRequires

[John Florian]

In my local Koji deployment I have one particular package (mdct-aos-flash) whose spec
%build has "%{__python3} -m unittest discover" so that my builds will fail if
any of the unit tests fail.  This has worked well for some time now.  Recently I added
another unit test which requires another locally built package (python3-mdct) to assist
with the test.  My first build submission failed and I immediately realized that I of
course needed to add this other package as a BuildRequires.  I did that and was surprised
to find the build still failing.  The root.log shows:

DEBUG package_manager.py:77:  ['/usr/bin/yum-builddep', '--installroot',
'/var/lib/mock/f21-build-1274-3319/root/',
'/var/lib/mock/f21-build-1274-3319/root//builddir/build/SRPMS/mdct-aos-flash-3.1-1.git.5.401b5db.fc21.src.rpm']
DEBUG util.py:508:  child environment: None
DEBUG util.py:441:  Executing command: ['/usr/bin/yum-builddep',
'--installroot', '/var/lib/mock/f21-build-1274-3319/root/',
'/var/lib/mock/f21-build-1274-3319/root//builddir/build/SRPMS/mdct-aos-flash-3.1-1.git.5.401b5db.fc21.src.rpm',
'--setopt=tsflags=nocontexts'] with env {'LANG': 'en_US.UTF-8',
'TERM': 'vt100', 'SHELL': '/bin/bash',
'LC_MESSAGES': 'C', 'PROMPT_COMMAND': 'printf
"\x1b]0;<mock-chroot>\x07<mock-chroot>"', 'PATH':
'/usr/bin:/bin:/usr/sbin:/sbin', 'HOME': '/builddir',
'HOSTNAME': 'mock'} and shell False
DEBUG util.py:377:  Getting requirements for mdct-aos-flash-3.1-1.git.5.401b5db.fc21.src
DEBUG util.py:377:   --> python3-devel-3.4.1-18.fc21.x86_64
DEBUG util.py:377:   --> python3-libs-3.4.1-18.fc21.x86_64
DEBUG util.py:377:   --> systemd-216-25.fc21.x86_64
DEBUG util.py:377:  Error: No Package found for python3-mdct
DEBUG util.py:488:  Child return code was: 1

Now I'm stumped.  Koji builds python3-mdct for f21 so I would expect that it's
just available to be pulled in as needed.  I have Koji configured to use our local mirrors
of Fedora as external-repos because we certainly depend on much of that, but I
wouldn't think it necessary to do so for our own repo.  My understanding of the
external-repos is to give Koji access to rpms which it may need, but itself did not
build.

Is my understanding wrong or have I missed a step here?

--
John Florian