public void ShouldHandlePositiveAndNegativeOffsets()
        {
            var rule = new SettleRuleBuilder()
                       .Minus(Period.FromMonths(1))
                       .Plus(Period.FromYears(1))
                       .Rule;

            Assert.Equal("-P1M+P1Y", rule.ToString());
        }
        public void ShouldHandleRoundingAndPositiveAndNegativeOffsets()
        {
            var rule = new SettleRuleBuilder()
                       .StartOf(SettleUnit.Month)
                       .Minus(Period.FromMonths(1))
                       .Plus(Period.FromYears(1))
                       .StartOf(SettleUnit.Day)
                       .Rule;

            Assert.Equal("month-P1M+P1Y_day", rule.ToString());
        }