public void ShouldThrowWhenNLessThan1Test()
 {
     Shouldly.ShouldThrowExtensions.ShouldThrow <ArgumentOutOfRangeException>(() =>
     {
         var sut = new EveryNthYearOnFrequencySpecialDayOfMonthStrategy(n: 0);
     });
 }
 public void ShouldThrowWhenSpecialDayGreaterThan9Test()
 {
     Shouldly.ShouldThrowExtensions.ShouldThrow <ArgumentException>(() =>
     {
         var sut = new EveryNthYearOnFrequencySpecialDayOfMonthStrategy(specialDay: (SpecialDay)10);
     });
 }