new_contents: import os.path
  from rdoupdate.bsource import BuildSource
  from rdoupdate.utils.cmd import run
  from rdoupdate.exception import FileExists
  
  
  def touch(f):
      if os.path.exists(f):
          raise FileExists(path=f)
      run('touch', f)
  
  class DummyFetcher(BuildSource):
      name = 'dummy'
  
      def _download_build(self, build_id):
          touch('%s.dummy.rpm' % build_id)
          touch('%s.dummy.src.rpm' % build_id)
  
      def _build_available(self, build_id):
          return True
  
subject: Add dummy build source