Running Xvfb during a package build -- good idea?

["Richard W.M. Jones" <rjones redhat com>]

We have a package (mingw32-openssl) which has some tests that run
under Wine.  Strictly speaking, running the tests isn't necessary, but
because it's such an important package I feel that we should run the
tests.

Anyhow, Wine needs an X server, although it doesn't really use it for
anything.  To provide one, I'm using Xvfb like this:

  BuildRequires:  wine
  BuildRequires:  xorg-x11-server-Xvfb

  #...

  display=:21
  Xvfb $display & xpid=$!
  trap "kill -TERM $xpid ||:" EXIT
  sleep 3
  DISPLAY=$display
  export DISPLAY
  make -C test tests

This works, but there are two problems.  Firstly there isn't a good
way to choose a free display number, so I'm just picking one at random
here.  This assumes that port 6021 is free, also disallows any builds
that happen in parallel.  Secondly, will Koji let me do such a thing
at all?  Is there another / a better way?

Rich.

-- 
Richard Jones, Emerging Technologies, Red Hat  http://et.redhat.com/~rjones
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