public void DoubleUtils_Substract3Test()
        {
            double?double1 = new double?(1.0);
            double?double2 = null;
            double?result  = DoubleUtils.Substract(double1, double2);

            Assert.AreEqual(null, result);
        }
        public void DoubleUtils_Substract1Test()
        {
            double?double1 = new double?(1.0);
            double?double2 = new double?(1.0);
            double?result  = DoubleUtils.Substract(double1, double2);

            Assert.IsNotNull(result);
            Assert.AreEqual((byte)0, (byte)result);
            Assert.AreEqual((short)0, (short)result);
            Assert.AreEqual(0, (int)result);
            Assert.AreEqual(0L, (long)result);
            Assert.AreEqual(0.0f, (float)result, 1.0f);
            Assert.AreEqual(0.0, (double)result, 1.0);
            Assert.AreEqual("0.0", result.Value.ToString("0.0", CultureInfo.InvariantCulture));
            Assert.AreEqual(false, Double.IsNaN((double)result));
            Assert.AreEqual(false, Double.IsInfinity((double)result));
        }