public void AddRangeToSelectionTest()
{
DateTime date1 = new DateTime(2021, 3, 10);
calendar.SelectDate(date1);
DateTime date2 = new DateTime(2021, 3, 15);
DateTime date3 = new DateTime(2021, 3, 17);
DateTime[] dates = new DateTime[] { date2, date3 };
calendar.AddRangeToSelection(dates);
DateTime[] selectedDates = calendar.SelectedDates;
Assert.That(selectedDates, Has.Length.EqualTo(3));
Assert.That(selectedDates[0], Is.EqualTo(date1));
Assert.That(selectedDates[1], Is.EqualTo(date2));
Assert.That(selectedDates[2], Is.EqualTo(date3));
}