public void render_with_custom_markdown_formatting()
        {
            var message = "**Dude, you're trying to divide by zero!**";

            // This is registering a conversion to markdown text from any
            // exception of type DivideByZeroException
            ExceptionFormatting.AsMarkdown <DivideByZeroException>(ex => message);

            var exception = new DivideByZeroException();

            ExceptionFormatting.ToDisplayMessage(exception, out display)
            .ShouldBe(message);

            display.ShouldBe(ErrorDisplay.markdown);
        }
        public void ExternallyFormattedException()
        {
            ExceptionFormatting.AsMarkdown <InvalidTimeZoneException>(ex => "Invalid timezone, see [valid timezones](https://msdn.microsoft.com/en-us/library/system.timezone(v=vs.110).aspx)");

            throw new InvalidTimeZoneException();
        }