public void ValueWhenXIsOnTheEdges()
        {
            TrapezoidalFunction func = new TrapezoidalFunction(1.0, 2.0, 1.8, 1.5);

            Assert.AreEqual(func.Value(1.0), 0);
            Assert.AreEqual(func.Value(2.0), 0);
        }
        public void ValueWhenXisOutsideOfRange()
        {
            TrapezoidalFunction func = new TrapezoidalFunction(1.0, 2.0, 1.5, 1.8);

            Assert.AreEqual(func.Value(0.8), 0);
            Assert.AreEqual(func.Value(2.1), 0);
        }
        public void ValueWhenXBetweenCAndD()
        {
            TrapezoidalFunction func = new TrapezoidalFunction(1.0, 2.0, 1.8, 1.5);

            Assert.AreEqual(func.Value(1.5), 1);
            Assert.AreEqual(func.Value(1.8), 1);
            Assert.AreEqual(func.Value(1.6), 1);
        }
        public void ValueWhenXIsBetweenCandB()
        {
            TrapezoidalFunction func = new TrapezoidalFunction(1.0, 2.0, 1.6, 1.5);

            Assert.AreEqual(func.Value(1.8), 0.5);
        }
        public void ValueWhenXIsBetweenAandD()
        {
            TrapezoidalFunction func = new TrapezoidalFunction(1.0, 2.0, 1.8, 1.4);

            Assert.AreEqual(func.Value(1.2), 0.5);
        }