System.Globalization.TaiwanCalendar.GetDaysInMonth C# (CSharp) Method

        public override int GetDaysInMonth(int year, int month, int era) {
            return (helper.GetDaysInMonth(year, month, era));
        }

 public void PosTest1()
 {
     System.Globalization.Calendar tc = new TaiwanCalendar();
     Random rand = new Random(-55);
     int year = rand.Next(tc.MinSupportedDateTime.Year, tc.MaxSupportedDateTime.Year - 1911);
     int month = rand.Next(1, 12);
     int day = rand.Next(1, tc.GetDaysInMonth(year, month) + 1);
     DateTime dt = new DateTime(year, month, day);
     int era = tc.GetEra(dt);
     Assert.Equal(1, era);
 }