class RSpec::Support::Differ

def diff(actual, expected)
  diff = ""
  unless actual.nil? || expected.nil?
    if all_strings?(actual, expected)
      if any_multiline_strings?(actual, expected)
        diff = diff_as_string(coerce_to_string(actual), coerce_to_string(expected))
      end
    elsif no_procs?(actual, expected) && no_numbers?(actual, expected)
      diff = diff_as_object(actual, expected)
    end
  end
  diff.to_s
end