# File lib/test/unit/assertions.rb, line 849
      def assert_nothing_thrown(message="", &proc)
        _wrap_assertion do
          assert(block_given?, "Should have passed a block to assert_nothing_thrown")
          begin
            proc.call
          rescue => error
            extractor = ThrowTagExtractor.new(error)
            tag = extractor.extract_tag
            raise if tag.nil?
            full_message = build_message(message,
                                         "<?> was thrown when nothing was expected",
                                         tag)
            flunk(full_message)
          end
          assert(true, "Expected nothing to be thrown")
        end
      end