# File lib/test/unit/assertions.rb, line 1080
      def assert_raise_message(expected, message=nil)
        _wrap_assertion do
          full_message = build_message(message,
                                       "<?> exception message expected " +
                                       "but none was thrown.",
                                       expected)
          exception = nil
          assert_block(full_message) do
            begin
              yield
              false
            rescue Exception => exception
              true
            end
          end

          actual = exception.message
          diff = AssertionMessage.delayed_diff(expected, actual)
          full_message =
            build_message(message,
                          "<?> exception message expected but was\n" +
                          "<?>.?", expected, actual, diff)
          assert_block(full_message) do
            if expected.is_a?(Regexp)
              expected =~ actual
            else
              expected == actual
            end
          end
        end
      end