public void PositiveTestRealStrategy()
        {
            var strategy = new RealDiscriminantStrategy();
            var solver   = new QuadraticEquationSolver(strategy);
            var results  = solver.Solve(1, 10, 16);

            Assert.That(results.Item1, Is.EqualTo(new Complex(-2, 0)));
            Assert.That(results.Item2, Is.EqualTo(new Complex(-8, 0)));
        }
        public void NegativeTestRealStrategy()
        {
            var strategy   = new RealDiscriminantStrategy();
            var solver     = new QuadraticEquationSolver(strategy);
            var results    = solver.Solve(1, 4, 5);
            var complexNaN = new Complex(double.NaN, double.NaN);

            Assert.That(results.Item1, Is.EqualTo(complexNaN));
            Assert.That(results.Item2, Is.EqualTo(complexNaN));

            Assert.IsTrue(double.IsNaN(results.Item1.Real));
            Assert.IsTrue(double.IsNaN(results.Item1.Imaginary));
            Assert.IsTrue(double.IsNaN(results.Item2.Real));
            Assert.IsTrue(double.IsNaN(results.Item2.Imaginary));
        }