//-------------------------------------------------------------------------
        public virtual void test_zeroRate()
        {
            ZeroRatePeriodicDiscountFactors test = ZeroRatePeriodicDiscountFactors.of(GBP, DATE_VAL, CURVE);
            double relativeYearFraction          = ACT_365F.relativeYearFraction(DATE_VAL, DATE_AFTER);
            double discountFactor = test.discountFactor(DATE_AFTER);
            double zeroRate       = test.zeroRate(DATE_AFTER);

            assertEquals(Math.Exp(-zeroRate * relativeYearFraction), discountFactor);
        }