public static string ToDisplayString(this TestRunFrequency frequency)
        {
            switch (frequency)
            {
            case TestRunFrequency.Daily:
                return("Daily");

            case TestRunFrequency.Hourly:
                return("Hourly");

            case TestRunFrequency.Continuously:
                return("Continuously");

            default:
                Debug.Fail("Unhandled frequency type");
                return("");
            }
        }
        public static TimeSpan ToTimeSpan(this TestRunFrequency frequency)
        {
            switch (frequency)
            {
            case TestRunFrequency.Daily:
                return(TimeSpan.FromDays(1));

            case TestRunFrequency.Hourly:
                return(TimeSpan.FromHours(1));

            case TestRunFrequency.Continuously:
                return(TimeSpan.FromMilliseconds(-1));

            default:
                Debug.Assert(false, "Unhandled TestRunFrequency value");
                return(TimeSpan.FromMilliseconds(-1));
            }
        }