new_contents: from catkin_pkg.packages import find_packages_allowing_duplicates
  
  from .util import in_temporary_directory
  
  
  @in_temporary_directory
  def test_find_packages_allowing_duplicates_with_no_packages():
      res = find_packages_allowing_duplicates('.')
      assert isinstance(res, dict)
      assert not res
  
subject: add test