test.rb

#!/usr/bin/env ruby

all_user_procs = %x[/bin/ps -e -o uid,pid | /bin/egrep "^\s+[0-9]{3,4}"]

pids_by_user = all_user_procs.lines.inject(Hash.new{|h,k| h[k] = []}) do |h,line|
  (uid,pid) = line.split.map(&:to_i)
  h[uid] << pid
  h
end

(missing_uids, ps_procs) = pids_by_user.partition do |uid,pids|
  $USERS.select { |u| u.uid == uid }.empty?
end

missing_uids.each do |uid,pids|
  pids.each do |pid|
    do_fail("Process #{pid} is owned by a gear that's no longer on the system, uid: #{uid}")
  end
end

ps_procs = ps_procs.inject({}) do |h,(uid,pids)|
  name = $USERS.select { |u| u.uid == uid }.first.name
  h[name] = pids.uniq
  h
end