public virtual void flatVolTest()
        {
            double          constantVol       = 0.15;
            ConstantSurface impliedVolSurface = ConstantSurface.of("impliedVol", constantVol);

            System.Func <double, double> zeroRate = (double?x) =>
            {
                return(0.05d);
            };
            System.Func <double, double> zeroRate1 = (double?x) =>
            {
                return(0.02d);
            };
            double[] strikes = new double[] { 90d, 100d, 115d };
            foreach (double strike in strikes)
            {
                foreach (double time in TEST_TIMES)
                {
                    DeformedSurface localVolSurface = CALC.localVolatilityFromImpliedVolatility(impliedVolSurface, 100d, zeroRate, zeroRate1);
                    assertEquals(localVolSurface.zValue(time, strike), constantVol);
                }
            }
        }