Tests for PXE bare-metal provisioning helper server.

a part of blueprint general-bare-metal-provisioning-framework.

The deploy helper was landed without tests. This patch reinstates the
tests.

Change-Id: I690ec077e175dc37c2cc5f18170513b0e5bca103
Co-authored-by: Mikyung Kang <mkkang@isi.edu>
Co-authored-by: David Kang <dkang@isi.edu>
Co-authored-by: Ken Igarashi <igarashik@nttdocomo.co.jp>
Co-authored-by: Arata Notsu <notsu@virtualtech.jp>
Co-authored-by: Devananda van der Veen <devananda.vdv@gmail.com>
Prevent metadata updates until instance is active.

This avoids a race condition where setting metadata too early in the
build process can cause a build failure due to the VM not existing
in Xen.

bug 1100866

Change-Id: I702128799997d91d5f0c0ac189f619bfdf011988
Fix nova coverage.

Nova coverage was broken because additional coverage tests were added
that interfere with collecting coverage during unit testing. These new
tests were not properly excluded by the coverage unit test regex. Modify
the regex to exclude any tests of the form '.*test.*coverage.*'. This
allows `tox -ecover` and `run_tests.sh --coverage` to run properly.

Change-Id: Id35f50ec335707c9eadb0e7fb3aa0833661f7333
List servers having non-existent flavor should return empty list

When we catch the exception just return an empty list.

Fixes LP# 1102462

Change-Id: I730bd505c40fa76cb0ba687575e3c3882fee6254
Make compare_result show the difference in lists

If two lists had differed because one had an extra element, both lists
would be included in the exception message. If the lists were large (for
example the list of extensions) it could be very difficult trying to
figure out what is different between the two lists.

This change will show the items that only exist in the expected and/or
result and not the other list.

Change-Id: I6102faea037b4f5e31361adc9db81e79592b7008
Merge "Tests for PXE bare-metal provisioning helper server."
Merge "Prevent metadata updates until instance is active."
Merge "List servers having non-existent flavor should return empty list"
Merge "Make compare_result show the difference in lists"
Merge "Fix nova coverage."