public static void SlopeImplicit_Throws_DivideByZeroException(double Fx, double Fy)
 {
     Assert.Throws <DivideByZeroException>(() => GeometryLibrary.SlopeImplicit(Fx, Fy));
 }
        public static void SlopeImplicit(double Fx, double Fy, double expected)
        {
            double result = GeometryLibrary.SlopeImplicit(Fx, Fy);

            Assert.AreEqual(expected, result, Tolerance);
        }