find_files_to_test (Autotest)

    # File lib/autotest.rb, line 367
      def find_files_to_test(files=find_files)
        updated = files.select { |filename, mtime| self.last_mtime < mtime }

        p updated if $v unless updated.empty? || self.last_mtime.to_i == 0

        hook :updated, updated unless updated.empty? || self.last_mtime.to_i == 0

        updated.map { |f,m| test_files_for(f) }.flatten.uniq.each do |filename|
          self.files_to_test[filename] # creates key with default value
        end

        if updated.empty? then
          nil
        else
          files.values.max
        end
      end