# File lib/test/unit/assertions.rb, line 63
      def assert(boolean, message=nil)
        _wrap_assertion do
          case message
          when nil, String, Proc
          else
            error_message = "assertion message must be String or Proc: "
            error_message << "<#{message.inspect}>(<#{message.class}>)"
            raise ArgumentError, error_message, filter_backtrace(caller)
          end
          assert_block("assert should not be called with a block.") do
            !block_given?
          end
          assert_block(build_message(message, "<?> is not true.", boolean)) do
            boolean
          end
        end
      end