new_broadcasts_from

# File actioncable/lib/action_cable/test_helper.rb, line 149
      def new_broadcasts_from(current_messages, stream, assertion, &block)
        old_messages = current_messages
        clear_messages(stream)

        _assert_nothing_raised_or_warn(assertion, &block)
        new_messages = broadcasts(stream)
        clear_messages(stream)

        # Restore all sent messages
        (old_messages + new_messages).each { |m| pubsub_adapter.broadcast(stream, m) }

        new_messages
      end